Mitsugi Nagashima

Subendocardial contractile impairment in chronic ischemic myocardium: assessment by strain analysis of 3T tagged CMR

BackgroundThe purpose of this study was to quantify myocardial strain on the subendocardial and epicardial layers of the left ventricle (LV) using tagged cardiovascular magnetic resonance (CMR) and to investigate the transmural degree of contractile impairment in the chronic ischemic myocardium.Methods3T tagged CMR was performed at rest in 12 patients with severe coronary artery disease who had been scheduled for coronary artery bypass grafting. Circumferential strain (C-strain) at end-systole on subendocardial and epicardial layers was measured using the short-axis tagged images of the LV and available software (Intag; Osirix). The myocardial segment was divided into stenotic and non-stenotic segments by invasive coronary angiography, and ischemic and non-ischemic segments by stress myocardial perfusion scintigraphy. The difference in C-strain between the two groups was analyzed using the Mann-Whitney U-test. The diagnostic capability of C-strain was analyzed using receiver operating characteristics analysis.ResultsThe absolute subendocardial C-strain was significantly lower for stenotic (-7.5 ± 12.6%) than non-stenotic segment (-18.8 ± 10.2%, p < 0.0001). There was no difference in epicardial C-strain between the two groups. Use of cutoff thresholds for subendocardial C-strain differentiated stenotic segments from non-stenotic segments with a sensitivity of 77%, a specificity of 70%, and areas under the curve (AUC) of 0.76. The absolute subendocardial C-strain was significantly lower for ischemic (-6.7 ± 13.1%) than non-ischemic segments (-21.6 ± 7.0%, p < 0.0001). The absolute epicardial C-strain was also significantly lower for ischemic (-5.1 ± 7.8%) than non-ischemic segments (-9.6 ± 9.1%, p < 0.05). Use of cutoff thresholds for subendocardial C-strain differentiated ischemic segments from non-ischemic segments with sensitivities of 86%, specificities of 84%, and AUC of 0.86.ConclusionsAnalysis of tagged CMR can non-invasively demonstrate predominant impairment of subendocardial strain in the chronic ischemic myocardium at rest.

Double-Chambered Right Ventricle in Adulthood

Patients with double-chambered right ventricle presenting with symptoms in adulthood are rare. From 1990 to 2004, 4 adults and 9 children with double-chambered right ventricle underwent surgical correction. The surgical results and clinical data of the adults were compared with those of the pediatric patients. All adult patients had dyspnea on exertion, 3 children showed growth delay but the others were asymptomatic. The mean age at operation was 44.5 ± 6.3 years in adults and 5.2 ± 1.9 years in children. The mean pressure gradient between the anatomically lower right ventricle and the pulmonary artery was significantly higher in adults than in children (91.8 ± 14.1 vs. 42.2 ± 5.9 mm Hg). The pulmonary-to-systemic flow ratio in adults was significantly lower than in pediatric patients (1.2 ± 0.2 vs. 1.8 ± 0.3). All adults and 8 of the 9 children survived. There were no late deaths or re-operations, and all survivors were in New York Heart Association functional class I. Surgical correction of double-chambered right ventricle in adults gave satisfactory midterm results although right ventricular outflow tract obstruction and clinical symptoms were severe in these patients.

Transient ischemia-induced paresis and complete paraplegia displayed distinct reactions of microglia and macrophages

In this study, we perform a detailed analysis of the microglial and macrophage responses in a model of spinal cord ischemia and reperfusion (SCI/R) injury in Wistar rats. The rats underwent occlusion across the descending aorta for 13min, causing paraplegia or paresis of varying severity. They were divided into four groups based on neurological assessment: sham, mild paresis, moderate paresis, and severe (complete) paraplegia. To examine the origin of microglia and macrophages in the ischemic lesion, bone marrow from rats expressing green fluorescent protein (GFP) was transplanted into test subjects one month before performing SCI/R. Many GFP(+)/CD68(+) microglia and macrophages were present 7d after SCI/R. Resident (GFP(-)/Iba1(+)/CD68(-)) microglia and bone marrow-derived macrophages (BMDMs; GFP(+)/Iba1(+)/CD68(+)) colocalized in the mild group 7d after SCI/R. In the moderate group, BMDMs outnumbered resident microglia. A greater accumulation of BMDMs expressing insulin-like growth factor-1 (IGF-1) was observed in lesions in the severe group, relative to the moderate group. BMDMs in the severe group strongly expressed tumor necrosis factor α, interleukin-1β, and inducible nitric oxide synthase, in addition to IGF-1. A robust accumulation of BMDMs occupying the entire ischemic gray matter was observed only in the severe group. These results demonstrate that the magnitude of the microglial and BMDM responses varies considerably, and that it correlates with the severity of the neurological dysfunction. Remarkably, BMDMs appear to have a beneficial effect on the spinal cord in paresis. In contrast, BMDMs seem to exhibit both beneficial and harmful effects in severe paraplegia.

Anomalous subaortic left brachiocephalic vein in surgical cases and literature review.

Anomalous subaortic left brachiocephalic vein (ASLBV) is a rare systemic venous anomaly. We review our experience with patients associated with ASLBV who underwent cardiac surgery at three institutions. From 1989 to 2009, the medical records of surgically treated patients with ASLBV were analyzed; the incidence of ASLBV, clinical characteristics, and associated anatomical findings were assessed. Fifteen patients had ASLBV. All ASLBVs coursed left lateral to the aortic arch, passed under the ascending aorta anterior to the central pulmonary artery, and joined the right brachiocephalic vein. Fourteen patients had congenital heart disease (CHD), and the remaining patient did not have cardiac anomalies. Its incidence was 0.57% (14 of 2,449) in patients with CHD and only 0.02% (1 of 4,805) in patients without CHD. In patients with CHD, 73.3% (11 of 15) of the patients had conotruncal cardiac anomalies such as tetralogy of Fallot, ventricular septal defect with pulmonary atresia, truncus arteriosus, and interruption of the aortic arch. Eight patients had aortic arch anomalies, including right aortic arch and cervical aortic arch. The deletion of chromosomal 22q11.2 was confirmed in two patients, and one patient was diagnosed with DiGeorge syndrome. ASLBV was clinically silent even without any surgical intervention. ASLBV is a very rare anomaly and is highly associated with conotruncal cardiac anomalies and aortic arch anomalies, including right aortic arch and cervical aortic arch. Preoperative diagnosis is important when any surgical interventions are intended, especially, in patients with conotruncal cardiac anomalies. Clin. Anat. 23:950–955, 2010.

Migration of Distal Ventriculoperitoneal Shunt Catheter into the Pulmonary Artery

A 50-year-old man presented with an abdominal bulge 2 years after receiving a ventriculoperitoneal (VP) shunt for hydrocephalus. Chest radiography revealed that the peritoneal end of the catheter had migrated into the right pulmonary artery. Exploration through a small neck incision revealed that the shunt catheter had entered the internal jugular vein. The catheter was extracted and positioned in the subcutaneous space in preparation for reimplantation. This type of shunt migration is quite unusual, but it could cause lethal pulmonary infarction or arrhythmia. Follow-up radiography should be scheduled to detect such complications.

Preoperative Autologous Blood Donation for Cardiac Surgery in Children

Preoperative autologous blood donation has been shown to reduce homologous blood transfusion in cardiac operations, but there have been few reports of its use in children. Of 50 children aged 6 months to 5 years (weight, 6.1–14.8 kg) undergoing primary cardiac surgery for simple anomalies, 23 donated autologous blood before surgery, the other 27 were age and weight-matched controls. Two donations of 10 mL·kg−1 each were collected via the femoral vein under mild general anesthesia 12 ± 5 and 19 ± 7 days preoperatively. No complications related to autologous blood collection were observed. Homologous blood use was significantly less in the group given autologous blood (4.3%) compared to the control group (44.4%). There was no significant difference in hemoglobin levels between groups before, during or after the operation. Preoperative autologous blood donation appears to be safe and effective in reducing homologous transfusions, even in children weighing less than 15 kg.

Successful Revascularization by Pulse Infusion Thrombolysis in a Patient With Kawasaki Disease Combined With Acute Myocardial Infarction

A 24-year-old man was admitted to our hospital because of continuous anterior chest discomfort. He had a history of Kawasaki disease. He was diagnosed with an ST-segment elevation myocardial infarction, showing thrombotic occlusion of an aneurysm in the right coronary artery ([Fig. 1][1]A). Thrombus

Regional myocardial blood flow measured by stress multidetector computed tomography as a predictor of recovery of left ventricular function after coronary artery bypass grafting

BACKGROUND Multidetector-row computed tomography (MDCT) applications have expanded to evaluation of myocardial blood flow (MBF) and viability. We quantified regional MBF pre- and post-coronary artery bypass grafting (CABG) using adenosine stress and cardiac 64-MDCT, and investigated whether the results predict MBF and left ventricular (LV) function recovery after CABG. METHODS We studied 321 regions in 19 CABG patients who underwent adenosine stress 64-row MDCT perfusion imaging and cine magnetic resonance imaging pre- and post-CABG. Myocardial blood flow was estimated from linear regression equation slopes using Patlak plot analyses and compared with LV function by measuring wall thickening (%WT) using cine magnetic resonance imaging. RESULTS Overall mean MBFs were 1.39 +/- 0.49 and 1.95 +/- 0.49 mL/(g min) pre- and post-CABG (P < .0001). Myocardial blood flow in revascularized areas increased significantly (pre-CABG 1.18 +/- 0.45, post-CABG 1.99 +/- 0.66 mL/[g min], P < .001), whereas nonischemic areas showed no difference (1.79 +/- 0.70 and 1.97 +/- 0.46 mL/[g min], P = .14). Revascularized areas with preoperative MBF > or = 0.9 mL/(g min) showed significantly greater MBF improvement than those with preoperative MBF <0.9 mL/(g min) (P = .04). In patients with preoperative LV dysfunction (ejection fraction <40%), %WT in revascularized areas with pre-CABG MBF > or = 0.9 mL/(g min) improved significantly after CABG (pre-%WT 40.9 +/- 22.9, post-%WT 52.8 +/- 20.6, P = .03) versus those with pre-CABG MBF <0.9 mL/(g min) (pre-%WT 53.2 +/- 35.5, post-%WT 42.5 +/- 17.0, P = .40). CONCLUSIONS Our results demonstrated more significantly increased MBF post-CABG than pre-CABG, particularly in revascularized areas. Regional MBF before CABG may predict MBF and LV function recovery, in the short term, after CABG.

Cardiac surgery for annuloaortic ectasia and mitral regurgitation in an adult patient with dextrocardia

We report a surgical case of dextrocardia complicated with annuloaortic ectasia (AAE) and mitral regurgitation, which induced congestive heart failure. Preoperative electrocardiography-gated multidetector-row computed tomography (MDCT) showed the following complex cardiovascular abnormalities without motion artifacts: dextrocardia, situs inversus, polysplenia, AAE, absence of the inferior vena cava, azygos vein continuation, drainage of the hepatic vein into the right atrium, and bilateral superior venae cavae. On the basis of the MDCT data, we established a cardiopulmonary bypass; and a modified Bentall procedure (Piehler method) and mitral valve replacement were performed without complications.

Asynchronous contraction of the 2 ventricles caused by ventricular pacing after a Fontan-type operation in a patient with a biventricular heart

We treated a 6-year-old boy who had polysplenia syndrome and tetralogy of Fallot with a small right ventricle (RV), an atrial septal defect, a hemiazygos connection, and bilateral superior vena cava. Because the RV was too small for a biventricular repair to be performed, the patient underwent a total cavopulmonary shunt operation although his heart was biventricular and a pacemaker (VVI) had been implanted for management of the sick sinus syndrome complicated by polysplenia syndrome. After the operation, marked asynchronous contraction was noted between the morphological right and left ventricles and was probably responsible for the low cardiac output noted in this patient. In order to clarify the significance of the asynchronous contraction, we determined the cause of the low cardiac output by studying the time course of the volume changes in the morphological right and left ventricles during a cardiac cycle by using angiograms. In addition, we studied the interventricular flow dynamics by using pulsed-Doppler echocardiography. After a Fontan-type operation is performed on patients with a biventricular heart, the 2 ventricles may not function in perfect coordination when they have to work as 1 unit. These patients are likely to develop cardiac dysfunction due to interventricular to-and-fro flow dynamics. Asynchronous contraction between the 2 ventricles caused by abnormal interventricular conduction impaired the cardiac performance in the present case.