Risk factors for unsuccessful restoration of coronary flow reserve after coronary bypass surgery.

OBJECTIVES: Coronary flow reserve (CFR) is a strong predictor of cardiovascular events and prognosis in patients with coronary artery disease. This study aimed to evaluate preoperative factors associated with the unsuccessful restoration of CFR after coronary artery bypass grafting (CABG). METHODS: Included in this study were the 65 patients who presented with functionally significant left anterior descending artery (LAD) lesions confirmed by both fractional flow reserve (FFR) and instantaneous wave-free ratio (iFR), and who underwent successful CABG at our hospital within the study period. After CABG, graft patency was confirmed by coronary computed tomography angiography, and CFR in the LAD artery was measured by echocardiography. We defined postoperative CFR <2.5 as impaired CFR, and CFR ≥2.5 as preserved CFR. RESULTS: Of the 65 patients, 14 patients (22%) showed impaired CFR, while 51 patients had preserved CFR. Patients with impaired CFR had significantly higher HbA1c (6.7% vs. 6.0%, P < 0.01), greater use of insulin (43% vs. 4%, P < 0.01), longer lesion length (33 mm vs. 25 mm, P = 0.044), and lower iFR (0.69 vs 0.81, P = 0.01) than those with preserved CFR, although both groups had comparable FFR (0.65 vs 0.64, P = 0.46). In receiver operating characteristic curve analysis, iFR had a significantly larger area under the curve than FFR in terms of the prediction of impaired CFR (0.74 vs 0.42, P = 0.01). CONCLUSIONS: Poorly-controlled preoperative diabetes, greater reliance on insulin, longer lesion length and lower iFR were associated with postoperative impaired CFR, suggesting the involvement of microvascular dysfunction.

Impact of Graft Velocity on Saphenous Vein Graft Atherosclerosis after Coronary Artery Bypass Grafting.

PURPOSE: Saphenous vein grafts (SVGs) sometimes occur as vein graft stenosis or failure in coronary artery bypass grafting. The purpose of this study was to detect the factors affecting vein graft atherosclerosis. METHODS: We performed two analysis. In the first analysis, we enrolled 120 grafts using conventionally harvested saphenous vein graft (C-SVG) and followed-up with multiple coronary computed tomography angiography (CCTA). We examined the factors that contribute to the graft atherosclerosis defined by graft failure at subsequent CCTA or substantial progression of graft stenosis (a decrease of ≥0.6 mm in diameter). In the second analysis, 66 grafts using no-touch harvested saphenous vein graft (N-SVG) were compared with those in the first analysis using C-SVG, focusing on the differences in intraoperative factors using propensity score-matched analysis. RESULTS: In the first analysis, graft atherosclerosis+ group comprised 27 grafts, which had a larger SVG diameter, lower graft velocity, and higher graft/native ratio in diameter than the graft atherosclerosis- group. In the multivariable analysis, slow graft velocity and graft/native ≥2 in diameter were independently associated with the graft atherosclerosis. In the second analysis, the N-SVG group had a much greater graft velocity than the C-SVG group. CONCLUSION: Lower graft velocity and higher graft/native ratio in diameter were associated with the graft atherosclerosis. The N-SVG group had increased graft velocity, which may contribute to prevent the graft atherosclerosis.(Trial registration: UMIN Clinical Trial Registry no. UMIN000050482. Registered 3 March 2023, retrospectively registered.).

Persistent neo-aortic root dilatation and aortic valve insufficiency after arterial switch operation following prior pulmonary artery banding.

Although there have been great improvements in the short- and medium-term outcomes of the arterial switch operation (ASO) for transposition of the great arteries (TGA), some complications including pulmonary artery stenosis, aortic valve insufficiency, and aortic root dilatation have also been reported. After ASO, the original pulmonary root and valve, which function in the systemic position as the neo-aortic root and valve respectively, are exposed to the systemic blood pressure, resulting in aortic root dilatation and valve insufficiency in some patients. One of the risk factors for these complications is a history of prior pulmonary artery banding (PAB). Complex TGA anatomy, including transposition of the great arteries and ventricular septal defect (TGA-VSD) or double outlet right ventricle and ventricular septal defect (DORV-VSD), is also an independent risk factor for neo-aortic dilatation and aortic valve regurgitation. Aortic valve and root replacement is sometime necessary for the patients with these pathologies long-term after ASO. Here, we present a patient who had persistent aortic sinus dilatation and aortic valve insufficiency since ASO and necessitating aortic root and valve replacement 15 years after ASO preceded by PAB. The patient underwent Bentall operation and his clinical course was favorable. Histological findings after root replacement revealed no remarkable structural difference between neo-aortic wall (originally pulmonary artery) and original aortic wall.

Simultaneous hybrid off-pump coronary artery bypass grafting and transcatheter aortic valve implantation in elderly patients.

Purpose: Optimal strategy for transcatheter aortic valve implantation (TAVI) in patients with coronary artery disease (CAD) is unresolved. We evaluated the surgical outcomes of hybrid coronary artery bypass grafting (CABG) and TAVI in elderly patients. Methods: We retrospectively evaluated patients who underwent simultaneous TAVI and CABG at Wakayama Medical University, Japan. All patients underwent off-pump CABG (OPCAB) including minimally invasive cardiac surgery (MICS-CABG). In an earlier period, OPCAB + transfemoral TAVI (TF-TAVI) was the only method used, while in a later period, we introduced MICS-CABG and alternative approaches for TAVI. Results: Twenty-seven patients were enrolled, the average age was 83.6 ± 5.1 years. In the MICS-CABG and TAVI group, average patient age was higher (87.0 ± 3.1 years) than in the earlier group. Thirty-day and in-hospital mortalities were zero. Incomplete revascularization rate was 33.3% and one patient required percutaneous coronary intervention after the operation. Graft patency rate was 100%. In MICS-CABG group, the number of distal anastomoses was smaller (1.29, range 1-2), but the number of days required to re-starting walking and postoperative hospital stay were shorter, and the rate of discharge to home was higher (100%) than in the other groups. Conclusions: Although 33.3% of patients did not achieve complete revascularization, there was no 30-day or in-hospital mortality. TAVI and hybrid OPCAB, including MICS-CABG, were suggested to be feasible treatment in elderly patients.

Corridor technique for coronary arteries from a single arterial sinus.

The introduction of the arterial switch operation has improved the surgical outcome of transposition of the great arteries. However, coronary anomalies such as intramural coronary arteries, single coronary artery, or coronary arteries originating from a single arterial sinus have been reported as independent risk factors for early mortality and late morbidity after an arterial switch operation. We performed an arterial switch operation using a unique technique for translocation of the coronary arteries originating from a single left-side arterial sinus, to prevent coronary artery distortion and subsequent coronary malperfusion.

Functional assessment of improvement of myocardial ischemia using coronary flow velocity reserve after coronary artery bypass surgery in hemodialysis.

BACKGROUND: In patients with end-stage renal disease requiring hemodialysis (HD patients), myocardial ischemia after coronary artery disease is a major cause of mortality. Coronary pathophysiology, namely myocardial microvascular dysfunction, appears to differ from patients not requiring HD (non-HD patients). OBJECTIVES: We compared functional improvement of myocardial ischemia after coronary artery bypass surgery (CABG) between HD and non-HD patients by transthoracic coronary flow velocity reserve (CFVR). METHODS: We retrospectively reviewed isolated CABG patients from between 2008 and 2017. Finally, 161 patients were enrolled; each underwent pre- and postoperative CFVR assessment, and left anterior descending (LAD) artery revascularization with "in-situ" internal mammary artery (IMA). Graft patency was confirmed, and after successful CABG, postoperative CFVR improvement between the two groups was compared. RESULTS: Preoperative CFVR value in group H was 1.81 ± 0.52, group N was 1.93 ± 0.66. There was no significant difference between the groups. IMA to LAD grafts were patent in postoperative evaluation in all patients. Postoperative CFVR in group H was 2.48 ± 0.72 and group N was 2.83 ± 0.73 (P = .042). Significant difference was observed. CONCLUSION: In both groups, CFVR values improved after successful CABG, but postoperative CFVR values were significant different. In younger populations CFVR values are generally higher. Our HD group was significantly younger than the non-HD group, but CFVR values were postoperatively significantly lower. CFVR values are reportedly affected by both epicardial and microcoronary circulation. In this study population, as all grafts to the LAD were patent, the lower CFVR value in the HD group was considered to have resulted in microvascular disorders.

Rapid growth of pulmonary artery after intrapulmonary artery septation.

Intrapulmonary artery septation is employed in patients with unbalanced pulmonary artery growth. A baby girl received a systemic pulmonary shunt in the neonatal period and bilateral Glenn shunts in early infancy. Once the Glenn shunts were established, the right pulmonary artery became hypoplastic. We performed intrapulmonary artery septation involving the Glenn shunts to the left pulmonary artery and the systemic pulmonary shunt to the right pulmonary artery. As early as 3 months after intrapulmonary artery septation, right pulmonary artery growth was observed. Eventually, Fontan circulation was achieved with fenestration.

Pulmonary vein obstruction after primary sutureless pericardial repair of a total anomalous pulmonary venous connection.

Total anomalous pulmonary venous connection is a rare congenital heart disease. The development of pulmonary venous obstruction is one of the major risk factors for poor outcomes after surgical repair. Sutureless pericardial repair for a total anomalous pulmonary venous connection was introduced to decrease the risk of pulmonary venous obstruction after surgical repair, and favourable outcomes have been reported. Herein, we report the case of an infant with a total anomalous pulmonary venous connection who developed pulmonary venous obstruction after primary sutureless pericardial repair.

Microstructural Alterations and Oligodendrocyte Dysmaturation in White Matter After Cardiopulmonary Bypass in a Juvenile Porcine Model.

BACKGROUND: Newly developed white matter (WM) injury is common after cardiopulmonary bypass (CPB) in severe/complex congenital heart disease. Fractional anisotropy (FA) allows measurement of macroscopic organization of WM pathology but has rarely been applied after CPB. The aims of our animal study were to define CPB-induced FA alterations and to determine correlations between these changes and cellular events after congenital heart disease surgery. METHODS AND RESULTS: Normal porcine WM development was first assessed between 3 and 7 weeks of age: 3-week-old piglets were randomly assigned to 1 of 3 CPB-induced insults. FA was analyzed in 31 WM structures. WM oligodendrocytes, astrocytes, and microglia were assessed immunohistologically. Normal porcine WM development resembles human WM development in early infancy. We found region-specific WM vulnerability to insults associated with CPB. FA changes after CPB were also insult dependent. Within various WM areas, WM within the frontal cortex was susceptible, suggesting that FA in the frontal cortex should be a biomarker for WM injury after CPB. FA increases occur parallel to cellular processes of WM maturation during normal development; however, they are altered following surgery. CPB-induced oligodendrocyte dysmaturation, astrogliosis, and microglial expansion affect these changes. FA enabled capturing CPB-induced cellular events 4 weeks postoperatively. Regions most resilient to CPB-induced FA reduction were those that maintained mature oligodendrocytes. CONCLUSIONS: Reducing alterations of oligodendrocyte development in the frontal cortex can be both a metric and a goal to improve neurodevelopmental impairment in the congenital heart disease population. Studies using this model can provide important data needed to better interpret human imaging studies.

Hypoxia diminishes the protective function of white-matter astrocytes in the developing brain.

OBJECTIVES: White-matter injury after surgery is common in neonates with cerebral immaturity secondary to in utero hypoxia. Astrocytes play a central role in brain protection; however, the reaction of astrocytes to hypothermic circulatory arrest (HCA) remains unknown. We investigated the role of astrocytes in white-matter injury after HCA and determined the effects of preoperative hypoxia on this role, using a novel mouse model. METHODS: Mice were exposed to hypoxia from days 3 to 11, which is equivalent to the third trimester in humans (prehypoxia, n = 49). Brain slices were transferred to a chamber perfused by cerebrospinal fluid. Oxygen-glucose deprivation (OGD) was performed to simulate ischemia-reperfusion/reoxygenation resulting from circulatory arrest under hypothermia. Astrocyte reactions were compared with preoperative normoxia (prenormoxia; n = 45). RESULTS: We observed astrocyte activation after 25°C ischemia-reperfusion/reoxygenation in prenormoxia (P < .01). Astrocyte number after OGD correlated with caspase-3(+) cells (rho = .77, P = .001), confirming that astrogliosis is an important response after HCA. At 3 hours after OGD, astrocytes in prenormoxia had already proliferated and become activated (P < .05). Conversely, astrocytes that developed under hypoxia did not display these responses. At 20 hours after ischemia-reperfusion/reoxygenation, astrogliosis was not observed in prehypoxia, demonstrating that hypoxia altered the response of astrocytes to insult. In contrast to prenormoxia, caspase-3(+) cells in prehypoxia increased after ischemia reperfusion/reoxygenation, compared with control (P < .01). Caspase-3(+) cells were more common with prehypoxia than with prenormoxia (P < .001), suggesting that lack of astrogliosis permits increased white-matter injury. CONCLUSIONS: Preoperative hypoxia alters the neuroprotective function of astrocytes. Restoring this function before surgery may be a therapeutic option to reduce postoperative white-matter injury in the immature brain.

Prolonged White Matter Inflammation After Cardiopulmonary Bypass and Circulatory Arrest in a Juvenile Porcine Model.

BACKGROUND: White matter (WM) injury is common after neonatal cardiopulmonary bypass (CPB). We have demonstrated that the inflammatory response to CPB is an important mechanism of WM injury. Microglia are brain-specific immune cells that respond to inflammation and can exacerbate injury. We hypothesized that microglia activation contributes to WM injury caused by CPB. METHODS: Juvenile piglets were randomly assigned to 1 of 3 CPB-induced brain insults (1, no-CPB; 2, full-flow CPB; 3, CPB and circulatory arrest). Neurobehavioral tests were performed. Animals were sacrificed 3 days or 4 weeks postoperatively. Microglia and proliferating cells were immunohistologically identified. Seven analyzed WM regions were further categorized into 3 fiber connections (1, commissural; 2, projection; 3, association fibers). RESULTS: Microglia numbers significantly increased on day 3 after CPB and circulatory arrest, but not after full-flow CPB. Fiber categories did not affect these changes. On post-CPB week 4, proliferating cell number, blood leukocyte number, interleukin (IL)-6 levels, and neurologic scores had normalized. However, both full-flow CPB and CPB and circulatory arrest displayed significant increases in the microglia number compared with control. Thus brain-specific inflammation after CPB persists despite no changes in systemic biomarkers. Microglia number was significantly different among fiber categories, being highest in association and lowest in commissural connections. Thus there was a WM fiber-dependent microglia reaction to CPB. CONCLUSIONS: This study demonstrates prolonged microglia activation in WM after CPB. This brain-specific inflammatory response is systemically silent. It is connection fiber-dependent which may impact specific connectivity deficits observed after CPB. Controlling microglia activation after CPB is a potential therapeutic intervention to limit neurologic deficits after CPB.

Effects of preoperative hypoxia on white matter injury associated with cardiopulmonary bypass in a rodent hypoxic and brain slice model.

BACKGROUND: White matter (WM) injury is common after cardiopulmonary bypass or deep hypothermic circulatory arrest in neonates who have cerebral immaturity secondary to in utero hypoxia. The mechanism remains unknown. We investigated effects of preoperative hypoxia on deep hypothermic circulatory arrest-induced WM injury using a combined experimental paradigm in rodents. METHODS: Mice were exposed to hypoxia (prehypoxia). Oxygen-glucose deprivation was performed under three temperatures to simulate brain conditions of deep hypothermic circulatory arrest including ischemia-reperfusion/reoxygenation under hypothermia. RESULTS: WM injury in prenormoxia was identified after 35 °C-oxygen-glucose deprivation. In prehypoxia, injury was displayed in all groups. Among oligodendrocyte stages, the preoligodendrocyte was the most susceptible, while the oligodendrocyte progenitor was resistant to insult. When effects of prehypoxia were assessed, injury of mature oligodendrocytes and oligodendrocyte progenitors in prehypoxia significantly increased as compared with prenormoxia, indicating that mature oligodendrocytes and progenitors that had developed under hypoxia had greater vulnerability. Conversely, damage of oligodendrocyte progenitors in prehypoxia were not identified after 15 °C-oxygen-glucose deprivation, suggesting that susceptible oligodendrocytes exposed to hypoxia are protected by deep hypothermia. CONCLUSION: Developmental alterations due to hypoxia result in an increased WM susceptibility to injury. Promoting WM regeneration by oligodendrocyte progenitors after earlier surgery using deep hypothermia is the most promising approach for successful WM development in congenital heart disease patients.

Rodent brain slice model for the study of white matter injury.

OBJECTIVE: Cerebral white matter (WM) injury is common after cardiac surgery in neonates and young infants who have brain immaturity and genetic abnormalities. To understand better the mechanisms associated with WM injury, we tested the adequacy of a novel ex vivo brain slice model, with a particular focus on how the maturational stage modulates the injury. METHODS: To replicate conditions of cardiopulmonary bypass, we transferred living brain slices to a closed chamber perfused by artificial cerebrospinal fluid under controlled temperature and oxygenation. Oxygen-glucose deprivation (OGD) simulated circulatory arrest. The effects of maturation were investigated in 7- and 21-day-old mice (P7, P21) that are equivalent in maturation stage to the human fetus and young adult. RESULTS: There were no morphologic changes in axons after 60 minutes of OGD at 15°C in both P7 WM and P21 WM. Higher temperature and longer duration of OGD were associated with significantly greater WM axonal damage, suggesting that the model replicates the injury seen after hypothermic circulatory arrest. The axonal damage at P7 was significantly less than at P21, demonstrating that immature axons are more resistant than mature axons. Conversely, a significant increase in caspase3(+) oligodendrocytes in P7 mice was identified relative to P21, indicating that oligodendrocytes in immature WM are more vulnerable than oligodendrocytes in mature WM. CONCLUSIONS: Neuroprotective strategies for immature WM may need to focus on reducing oligodendrocyte injury. The brain slice model will be helpful in understanding the effects of cardiac surgery on the immature brain and the brain with genetic abnormalities.

Rupture of Kommerell diverticulum after total arch replacement.

A 62-year-old man was brought to the emergency room of our hospital because of chest pain. Computed tomography revealed a right aortic arch and an aberrant left subclavian artery with Kommerell diverticulum and acute aortic dissection (Stanford type A). Total arch replacement was performed emergently through a median full sternotomy. A stomach feeding tube was placed postoperatively for the patient to receive nutrition, and esophageal bleeding was observed postoperatively. The patient died because of the bleeding. Autopsy findings showed a communication between the esophagus and Kommerell diverticulum. Rupture of Kommerell diverticulum and perforation of the esophagus were indicated.

Takedown of Yasui procedure due to closed ventricular septal defect.

A two and a half year old girl who had undergone the Yasui procedure as a neonate for ventricular septal defect, subaortic stenosis, and interrupted aortic arch underwent follow-up catheterization 2 years postoperatively. It showed that the neo-left ventricular tract reconstructed by Damus-Kaye-Stansel anastomosis had occluded due to closure of the ventricular septal defect and residual subaortic stenosis at the original left ventricular outflow tract. The patient therefore underwent takedown of the Yasui procedure.

Remarkable giant right atrial diverticulum in asymptomatic patient.

We describe the case of a 31-year-old man who had a giant right atrial diverticulum. Although he was asymptomatic, preoperative echocardiography and three-dimensional computed tomography scan found a large mass on the right atrium. He was diagnosed with a right atrial diverticulum and underwent surgical resection of the diverticulum because of the risk of thromboembolism, arrhythmia and rupture of the diverticulum. Intra-operative finding was compatible with the feature of a diverticulum which includes thin wall and large space inside the diverticulum. Postoperative pathological examination showed a thin diverticulum wall consisting of only fibrous tissue and intima without muscular tissue. We concluded that a large diverticulum should be treated surgically because of the critical complications.

Surgical palliation for Taussig-Bing anomaly with multiple lesions.

A successful surgical palliative procedure, consisting of an arterial switch operation, pulmonary artery banding, and arch repair, was performed in a neonate with Taussig-Bing anomaly and aortic arch interruption, subaortic stenosis, and multiple muscular ventricular septal defects. Such anatomical complexity made treatment difficult. This palliative procedure allows future biventricular repair.

[Complex myxoma detected by syncope: a case report].

A 23-year-old man was admitted to our hospital for evaluation of syncope and intracardiac masses. Echocardiography revealed three masses in the right ventricle and one in the left ventricle. The largest mass, 4 by 5 cm, occupied the right ventricular outflow tract and prolapsed through the pulmonary valve orifice. Right ventricular systolic pressure was 65 mmHg. A soft mass, 4 by 5 cm, was found on the left subcostal abdominal wall and multiple pigmented spots on the face and trunk. Histological examination of the resected tumors, including the abdominal soft mass, were consistent with myxoma. The combination of multiple cardiac and abdominal wall myxomas and pigmented skin lesions in this young patient is considered to be a diagnostic feature of Carney complex.