Search

Background: There is no consensus regarding thromboprophylaxis after Fontan procedure, and novel tools to assess thrombogenicity are needed to establish optimal thromboprophylaxis. The Total Thrombus-formation Analysis System (T-TAS) was developed for the quantitative analysis of thrombus formation using microchips with thrombogenic surfaces. This prospective study evaluated the utility of T-TAS in the assessment of thrombogenicity in pediatric Fontan patients., Methods and Results: The participants included 20 consecutive Fontan patients who underwent cardiac catheterization and 30 healthy controls. Blood samples collected without and with antithrombotic therapy (aspirin or aspirin and warfarin) were used for T-TAS to compute the area under the curve (AUC) in the atheroma (AR 10 -AUC 30 ) and platelet (PL 18 -AUC 10 ) chips. A higher AUC indicates higher thrombogenicity. T-TAS values showed that patients in the Fontan group without antithrombotic therapy had lower thrombogenicity than those in the control group [PL 18 -AUC 10 , median (interquartile range) 356 (313-394) vs. 408 (392-424); AR 10 -AUC 30 , median (interquartile range) 1270 (1178-1351) vs. 1382 (1338-1421)]. Aspirin and warfarin therapies significantly decreased PL 18 -AUC 10 and AR 10 -AUC 30 , respectively, compared with those of patients without antithrombotic therapy (P < 0.001 for each comparison). Subgroup analysis divided by low (< 9 mmHg) or high (≥ 9 mmHg) central venous pressure (CVP) showed that CVP affects the reduction in AR 10 -AUC 30 with antithrombotic therapy., Conclusions: T-TAS may be a useful tool for monitoring thrombogenicity and antithrombotic therapy in Fontan patients., (© 2022. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

Clinicians are currently encountering an increasing number of patients in the long-term period after tetralogy of Fallot (TOF) repair presenting with pulmonary valve regurgitation (PR) or right ventricular (RV) dysfunction. The purpose of this study was to evaluate the clinical utility of the plasma brain natriuretic peptide (BNP) level and consider surgical indications and timing of pulmonary valve replacement (PVR). We examined 33 patients (21 males, 12 females, mean age 14.5 ± 2.8 years) who underwent TOF repair at Kitasato University Hospital. All patients were evaluated using echocardiography and blood sampling. The mean age at the time of initial repair was 1.3 ± 0.7 years. The patients with moderate-severe PR exhibited significantly higher plasma BNP levels than the patients with trivial-mild PR (mean 37.5 ± 33.1 vs. 17.3 ± 6.6 pg/ml, p = 0.013). The mean plasma BNP level with cardiac symptoms was higher than that observed in the patients without any symptoms (71.4 ± 46.1 vs. 25.0 ± 14.0 pg/ml, p = 0.005). The mean BNP level was significantly decreased after PVR (71.3 ± 46.1-26.1 ± 13.2 pg/ml, p = 0.009), and the plasma BNP level was found to be positively correlated with the RV end-diastolic pressure (r = 0.851; p = 0.008). The optimal BNP cut-off value for considering PVR was 32.15 pg/ml (sensitivity, 85.7 %; specificity, 83.3 %). The plasma BNP level may become a useful diagnostic tool for considering the indications and optimal timing of PVR over the long term after TOF repair.

Flow energy loss (EL) at the Fontan anastomosis has been thought to reflect flow efficiencies and to influence on hemodynamics in the Fontan circulation and has been often discussed in numerical studies. However, in vivo EL measurements have to date not been reported. We directly measured EL in the Fontan circulation and examined the relationship between the structural configuration and EL, as well as the influence of EL, on the hemodynamics in the Fontan circulation. We performed a catheterization study measuring simultaneous pressure and flow velocity to calculate EL in nine patients (mean age 2.3 ± 0.3 years) 1 year after the Fontan procedure. The measured EL was 9.66 ± 8.50 mW. One patient with left pulmonary artery stenosis recorded the highest EL (17.78 mW), and one patient with bilateral superior vena cava and left phrenic nerve palsy recorded the second highest EL (14.62 mW). EL significantly correlated with time constant tau and weakly with max-dp/dt during the isovolumic diastolic phase (r = 0.795 and -0.574, respectively). EL also correlated with max-dp/dt during the isovolumic systolic phase (r = 0.842) but not with ejection fraction or systemic blood flow (r = 0.384 and -0.034, respectively). In conclusion, inefficient structural configuration and phrenic nerve palsy seem to be related with increased in EL at the Fontan anastomosis. Although these preliminary findings also suggest that EL is associated with an impaired relaxation of the ventricle, a long-term study with a large population is warranted to reach such a definitive conclusion.

At our institution, the strategy for patients with bicuspid aortic valve, aortic valve stenosis (<5 mm), and aortic hypoplasia [hypoplastic aortic arch, coarctation of the aorta (CoA), or interrupted aortic arch (IAA)] with ventricular septal defects (VSDs) as well as normal left ventricular (LV) volume and mitral valve size consists of two parts. The Norwood operation is applied as the first palliation for this group of patients. Second, the decision whether the patients are to undergo the Rastelli operation or a univentricular repair is made depending on the size of the right ventricle after the Norwood operation. This study aimed to examine whether the aforementioned surgical strategy for this group of patients is adequate or not. Seven patients undergoing the Norwood operation as the first palliation for bicuspid aortic valve, aortic valve stenosis (<5 mm), and aortic hypoplasia with VSDs as well as normal LV volume and mitral valve size between February 2005 and March 2010 at Kitasato University Hospital and the Gunma Children's Medical Center were reviewed. Postoperative serum B-type natriuretic peptide (BNP) and central venous pressure (CVP) were measured in the patients undergoing the staged Norwood-Rastelli operation to assess whether the authors' right ventricular end-diastolic volume index (RVEDVI) cutoff (80 % of normal) is adequate. At this writing, all seven patients are alive after a mean follow-up period of 58.8 ± 17.8 months. They all had aortic valve stenosis of <5 mm and a bicuspid aortic valve. Four patients had a diagnosis of CoA with VSD, and three patients had IAA with VSD. Six patients underwent biventricular repair, and one patient had univentricular repair due to the small RVEDVI (74 % of normal). The patients with 80-90 % of normal RVEDVI had higher BNP and higher CVP than those with more than 90 % of normal RVEDVI after the Rastelli operation, whereas the patient undergoing the Fontan operation had a low BNP level. In conclusion, the described strategy for patients with severe aortic hypoplasia and aortic stenosis with VSD as well as normal LV and mitral valve size is reasonable.

Because the cavopulmonary shunt procedure is widely used for palliation of complex congenital heart diseases, pulmonary arteriovenous malformations (PAVMs) are relatively well-known complications. The reported patient was a 23-year-old woman who experienced PAVMs in the right lower lobe after a classical Glenn anastomosis and Björk procedure for tricuspid atresia. Her arterial oxygen saturation (SaO2) 14 years after the Björk procedure was ~80 %. She then underwent a total cavopulmonary connection (TCPC) conversion to reduce her PAVMs in the right lower lobe using the "hepatic factor." However, her situation remained unchanged, and she experienced severe systemic cyanosis (SaO2, 70 %) and dyspnea during physical exertion without hemoptysis due to increased blood flow to the PAVMs. Although interventional embolization was considered, it was impossible due to considerable dilation of the main PAVM. Thus, right lower lung lobectomy was performed. After surgery, the patient's SaO2 increased to 90 %. To the authors' knowledge, this is the first case report of a lung resection for residual PAVMs after TCPC conversion.

We assessed the usefulness of transthoracic Doppler-derived indexes obtained in the proximal pulmonary artery (PA) branch for estimating pulmonary vascular resistance (PVR) in 45 children with congenital heart disease (CHD) and 23 normal control subjects. The acceleration time, inflection time (InT), deceleration index, and peak velocity, which were measured from the systolic PA flow velocity curve obtained at the sites of the main PA, and right and left PA, were compared with the PVR in patients with CHD. In addition, changes in either Doppler-derived indexes or PVR during 100% oxygen administration were compared in 22 patients showing a baseline PVR >or=4.6 U/m(2) (high PVR). The heart-rate-corrected InT (InTc) values obtained in the left PA in the high PVR group were significantly lower than those in the main PA (4.7 +/- 1.5 vs. 7.5 +/- 3.0; p < 0.001). The InTc obtained from the left PA separated patients with high and low PVR (4.7 +/- 1.4 vs. 9.9 +/- 2.4; p < 0.001) and no significant differences in InTc were found between the low PVR and the control groups. An increase in InTc to >6 during 100% oxygen administration for the high PVR group indicated good PA reactivity with a sensitivity of 93%, specificity of 100%, and agreement of 95% (kappa = 0.83). Moreover, this InTc index correlated inversely with PVR (r = -0.80). In conclusion, our method can noninvasively separate high and low PVR and assess the PA reactivity for high PVR in children with CHD.

We retrospectively investigated the effect of warfarin therapy in improving the clinical outcome of Kawasaki disease (KD) patients with giant coronary aneurysms (GAs). We followed 2350 KD patients from 1973 to 2004. The GAs (> or =8 mm in diameter) were diagnosed by coronary angiography. Sixty-eight patients (54 males and 14 females) were retrospectively studied. Patients were divided into two groups. One group consisted of 19 patients with 33 branches treated with a combination of low-dose aspirin and warfarin (target international normalized ratio: 1.5 - 2.5 IU). The second group consisted of 49 patients with 102 branches treated with low-dose aspirin without warfarin. The incidence of myocardial infarction was significantly less in the combination therapy group than in patients treated with aspirin without warfarin (1 patient vs. 16 patients, p < 0.05). Sudden death occurred in seven patients taking aspirin without warfarin, but none of the patients receiving warfarin died. No major bleeding events occurred in either group. Combination therapy of warfarin with aspirin is associated with a decreased risk of myocardial infarction in KD patients with GAs.