Comparison of Clinical Outcomes in Patients Undergoing a Salvage Procedure for Thrombosed Hemodialysis Arteriovenous Grafts.

BACKGROUND: The major limitation of arteriovenous graft access is the high incidence of thrombotic occlusion. This study investigated the outcomes of our salvage strategy for thrombosed hemodialysis arteriovenous grafts (including surgical thrombectomy with balloon angioplasty) and evaluated the efficacy of intragraft curettage. METHODS: Salvage operations were performed for 290 thrombotic occluded arteriovenous grafts with clinical stenotic lesions from 2010 to 2018. Of these, 117 grafts received surgical thrombectomy and balloon angioplasty from 2010 to 2012 (group A), and 173 grafts received surgical thrombectomy and balloon angioplasty, with an additional salvage procedure using a curette and a graft thrombectomy catheter, from 2013 to 2018 (group B). Outcomes were described in terms of post-intervention primary patency and secondary patency rates. RESULTS: The post-intervention primary patency rates in groups A and B were 44.2% and 66.1% at 6 months and 23.0% and 38.3% at 12 months, respectively (p=0.003). The post-intervention secondary patency rates were 87.6% and 92.6% at 6 months and 79.7% and 85.0% at 12 months, respectively (p=0.623). Multivariate Cox regression analysis demonstrated that intragraft curettage was a positive predictor of post-intervention primary patency (hazard ratio, 0.700; 95% confidence interval, 0.519-0.943; p=0.019). CONCLUSION: Surgical thrombectomy and balloon angioplasty showed acceptable outcomes concerning post-intervention primary and secondary patency rates. Additionally, intragraft curettage may offer better patency to salvage thrombotic occluded arteriovenous grafts with intragraft stenosis.

Sternal Resection and Reconstruction for Solitary Plasmacytoma of the Sternum: Case Report.

A 63-year-old patient was admitted with a sternal fracture and mass. On evaluation, most of the body of the sternum had been destroyed by a tumor. Radical resection of the sternum was performed and part of the major pectoral muscles adherent to the sternal tumor was also resected. The chest wall defect was reconstructed with mesh, bone cement, and a titanium rib plate system. Reconstruction with this method seemed to be an appropriate procedure to prevent instability of the chest wall.

Histologic Analysis with the Newly Designed Exoskeleton Seal® Stent-Graft in the Porcine Abdominal Aorta.

PURPOSE: To investigate the technical feasibility of a novel exoskeleton Seal® stent-graft and analyze early histologic changes in the porcine abdominal aorta. MATERIALS AND METHODS: Six pigs received an abdominal stent-graft (Group I), and six received an iliac branch stent-graft (Group II). Groups were subdivided as follows: Group Ia, which received three bifurcated main-body stent-grafts; Group Ib, which received three bifurcated main-body stent-grafts with both iliac graft-stents; Group IIa, which received three simple uni-iliac tapered stent-grafts; and Group IIb, which received three uni-iliac tapered tapered stent-grafts with right straight limb and left branched limb. Statistical analyses were performed with the Wilcoxon signed-rank test and mixed-model regression analysis. RESULTS: The primary technical success rate (< 24 h) was 83% because of two acute thromboses in the lumen of the stented abdominal aorta immediately after stent-graft placement. At 4 weeks, late thrombosis occurred in two pigs. Higher mean neointimal hyperplasia areas (23.5% vs. 16.2%; P = .047), neointimal hyperplasia thicknesses (545.5 µm vs. 422.2 µm; P = .001), and degrees of collagen deposition (2.71 vs. 2.33; P = .002) were observed at the bare-metal stent-graft compared with the proximal exoskeleton portion of the stent-graft, with no significant differences between the patent and occluded groups or among the four types of stent-grafts. CONCLUSIONS: The exoskeleton stent-graft demonstrates 66% of patency rate during 1-month follow-up due to four cases of thromboses; however, the endothelialization on the junction of proximal graft showed no significant differences between the patent and occluded groups. Further studies should investigate long-term outcomes with prolonged neointimal hyperplasia.

Windkessel model of hemodynamic state supported by a pulsatile ventricular assist device in premature ventricle contraction.

BACKGROUND: Counter-pulsation control (CPC) by ventricular assist devices (VADs) is believed to reduce cardiac load and increase coronary perfusion. However, patients with VADs have a higher risk of arrhythmia, which may cause the CPC to fail. Consequently, CPC has not been applied by VADs in clinical practice. The phase-locked loop (PLL) algorithm for CPC is readily implemented in VADs; however, it requires a normal, consistent heartbeat for adequate performance. When an arrhythmia occurs, the algorithm maintains a constant pumping rate despite the unstable heartbeat. Therefore, to apply the PLL algorithm to CPC, the hemodynamic effects of abnormal heartbeats must be analyzed. OBJECTIVES: This study sought to predict the hemodynamic effects in patients undergoing CPC using VADs, based on electrocardiogram (ECG) data, including a wide range of heart rate (HR) changes caused by premature ventricular contraction (PVC) or other reasons. METHODS: A four-element Windkessel hemodynamic model was used to reproduce the patient's aortic blood pressure in this study. ECG data from 15 patients with severe congestive heart failure were used to assess the effect of the CPC on the patients' hemodynamic state. The input and output flow characteristics of the pulsatile VAD (LibraHeart I, Cervika, Korea) were measured using an ultrasound blood flow meter (TS410, Transonic, USA), with the aortic pressure maintained at 80-120 mmHg. All other patient conditions were also reproduced. RESULTS: In patients with PVCs or normal heartbeats, CPC controlled by a VAD reduced the cardiac load by 20 and 40%, respectively. When the HR was greater for other reasons, such as sinus tachycardia, simultaneous ejection from the heart and VAD was observed; however, the cardiac load was not increased by rapid cardiac contractions resulting from decreased left ventricle volume. These data suggest that the PLL algorithm reduces the cardiac load and maintains consistent hemodynamic changes.

Myocardial CT perfusion imaging for pre- and postoperative evaluation of myocardial ischemia in a patient with myocardial bridging: A case report.

RATIONALE: Although myocardial bridging (MB) is usually considered as benign, initial medical therapy and following surgical treatment in drug-refractory cases has been widely accepted for managing symptomatic MB. Before the patient proceeds to percutaneous or surgical intervention, however, the presence of objective ischemia in the corresponding myocardial territory should be documented. PATIENT CONCERN AND INTERVENTION: We herein report a 43-year-old male complaining of chest pain in whom cardiac CT with myocardial perfusion (cCTP) showed an MB of left anterior descending artery (LAD) with preoperative perfusion defect in corresponding myocardium and normalization of perfusion after supra-arterial myotomy. DIAGNOSIS: Myocardial bridging-induced ischemia. LESSONS: This case illustrates the potential utility of cCTP for the simultaneous assessment of MB and its hemodynamic significance for treatment planning and post-therapeutic evaluation although further research is needed to establish the clinical usefulness of this technique.

Outflow monitoring of a pneumatic ventricular assist device using external pressure sensors.

BACKGROUND: In this study, a new algorithm was developed for estimating the pump outflow of a pneumatic ventricular assist device (p-VAD). The pump outflow estimation algorithm was derived from the ideal gas equation and determined the change in blood-sac volume of a p-VAD using two external pressure sensors. OBJECTIVES: Based on in vitro experiments, the algorithm was revised to consider the effects of structural compliance caused by volume changes in an implanted unit, an air driveline, and the pressure difference between the sensors and the implanted unit. METHODS: In animal experiments, p-VADs were connected to the left ventricles and the descending aorta of three calves (70-100 kg). Their outflows were estimated using the new algorithm and compared to the results obtained using an ultrasonic blood flow meter (UBF) (TS-410, Transonic Systems Inc., Ithaca, NY, USA). RESULTS: The estimated and measured values had a Pearson's correlation coefficient of 0.864. The pressure sensors were installed at the external controller and connected to the air driveline on the same side as the external actuator, which made the sensors easy to manage.

Two-stage Surgery for an Aortoesophageal Fistula Caused by Tuberculous Esophagitis.

An aortoesophageal fistula (AEF) is an extremely rare, potentially fatal condition, and aortic surgery is usually performed together with extracorporeal circulation. However, this surgical method has a high rate of surgical complications and mortality. This report describes an AEF caused by tuberculous esophagitis that was treated successfully using a two-stage operation. A 52-yr-old man was admitted to the hospital with severe hematemesis and syncope. Based on the computed tomography and diagnostic endoscopic findings, he was diagnosed with an AEF and initially underwent thoracic endovascular aortic repair. Esophageal reconstruction was performed after controlling the mediastinal inflammation. The patient suffered postoperative anastomotic leakage, which was treated by an endoscopic procedure, and the patient was discharged without any further problems. The patient received 9 months of anti-tuberculosis treatment after he was diagnosed with histologically confirmed tuberculous esophagitis; subsequently, he was followed as an outpatient and has had no recurrence of the tuberculosis or any further issues.

Retrograde guidewire fracture complicated with pericardial tamponade in chronic total occlusive coronary lesion.

Along with various coronary devices progress, there is a now growing trend to percutaneous coronary intervention for chronic total occlusion (CTO). However, the risk of guidewire fracture rate might be increased in complex lesion such as tortuous, calcific lesion or retrograde route. We report a case of successful surgical removal of fractured and entrapped guidewire in a septal channel during retrograde CTO intervention in a patient complicated with pericardial tamponade by delayed penetration of broken guidewire into pericardium.

Heart monitoring using left ventricle impedance and ventricular electrocardiography in left ventricular assist device patients.

BACKGROUND: Patients who develop critical arrhythmia during left ventricular assist device (LVAD) perfusion have a low survival rate. For diagnosis of unexpected heart abnormalities, new heart-monitoring methods are required for patients supported by LVAD perfusion. Ventricular electrocardiography using electrodes implanted in the ventricle to detect heart contractions is unsuitable if the heart is abnormal. Left ventricular impedance (LVI) is useful for monitoring heart movement but does not show abnormal action potential in the heart muscle. OBJECTIVES: To detect detailed abnormal heart conditions, we obtained ventricular electrocardiograms (v-ECGs) and LVI simultaneously in porcine models connected to LVADs. METHODS: In the porcine models, electrodes were set on the heart apex and ascending aorta for real-time measurements of v-ECGs and LVI. As the carrier current frequency of the LVI was adjusted to 30 kHz, it was easily derived from the original v-ECG signal by using a high-pass filter (cutoff: 10 kHz). In addition, v-ECGs with a frequency band of 0.1 - 120 Hz were easily derived using a low-pass filter. Simultaneous v-ECG and LVI data were compared to detect heart volume changes during the Q-T period when the heart contracted. A new real-time algorithm for comparison of v-ECGs and LVI determined whether the porcine heartbeats were normal or abnormal. Several abnormal heartbeats were detected using the LVADs operating in asynchronous mode, most of which were premature ventricle contractions (PVCs). To evaluate the accuracy of the new method, the results obtained were compared to normal ECG data and cardiac output measured simultaneously using commercial devices. RESULTS: The new method provided more accurate detection of abnormal heart movements. This method can be used for various heart diseases, even those in which the cardiac output is heavily affected by LVAD operation.

Totally endovascular aortic arch repair by branched stent graft placement.

Several methods for endovascular aortic arch repair have been proposed to reduce the morbidity and mortality associated with conventional open surgery for aortic arch aneurysms. We report our experience with aortic arch aneurysm repair by a totally endovascular technique, that is, a "reversed" stent graft technique using branched stent grafts.

Neovascularization and associated fistula formation in a left atrial myxoma: evaluation with multidetector computed tomography.

Although angiographically detectable neovascularity is being reported with increasing frequency in patients with cardiac myxoma, associated coronary fistula to the cardiac chamber has not been described. We report a 62-year-old woman in whom cardiac computed tomography (CT) enabled the noninvasive diagnosis of a left atrial myxoma with neovascularization arising from the left circumflex artery and the formation of an unusual fistula into the left atrial cavity, with concomitant evaluation of the coronary arteries. Careful suture ligation of a supplying coronary branch in the atrial septum was performed during tumor excision to prevent the development of intra-atrial steal.

Spontaneous intramural full-length dissection of esophagus treated with surgical intervention: multidetector CT diagnosis with multiplanar reformations and virtual endoscopic display.

Intramural esophageal dissection (IED) is an uncommon disorder characterized by separation of the mucosal and submucosal layers of the esophagus. Iatrogenic intervention is the most common cause of IED, but spontaneous dissection is rare. We report an unusually complicated case of spontaneous IED that involved the full-length of the esophagus that necessitated surgical intervention due to infection of the false lumen. In this case, chest computed tomography successfully established the diagnosis and aided in pre-operative evaluation with the use of various image post-processing techniques.

Lymphangiomatosis involving the inferior vena cava, heart, pulmonary artery and pelvic cavity.

A 38-year-old woman who had undergone pelvic lymphangioma resection two months previously presented with cough and dyspnea. Transthoracic echocardiography and CT demonstrated the presence of a mixed cystic/solid component tumor involving the inferior vena cava, heart and pulmonary artery. Complete resection of the cardiac tumor was performed and lymphangioma was confirmed based on histopathologic examination. To the best of our knowledge, this is the first report of lymphangiomatosis with cardiac and pelvic involvement in the published clinical literature.

A modified technique for preventing spinal cord ischemia during type II thoracoabdominal aneurysm repair.

A 51-year-old man required replacement of the thoracoabdominal aorta due to a type II thoracoabdominal aortic aneurysm. We tailored and plicated the aortic aneurysm to make a closed tube. All of the intercostal arteries and lumbar arteries were reimplanted using a closed tube constructed with an aneurysmoplasty to the main aortic graft, using this tube to protect the spinal cord. The closed tube maintained blood flow to the intercostal and lumbar arteries, and no neurologic deficits developed.

Concomitant peripheral artery disease and asymptomatic coronary artery disease: a management strategy.

The present study examines the use of routine coronary angiography (CAG) before elective peripheral artery disease (PAD) surgery and the early outcome and technical features of simultaneous coronary revascularization and PAD surgery in PAD patients with asymptomatic coronary artery disease (CAD). We performed preoperative CAG in 82 patients who were undergoing elective peripheral arterial bypass surgery and who had no diagnosis or symptoms of ischemic heart disease. The 82 patients were grouped according to the criteria of <70% stenosis, >70% stenosis, and no coronary stenosis. In patients with >70% coronary artery stenosis, we performed simultaneous peripheral artery bypass surgery and coronary artery bypass grafting (CABG), while the other patients underwent peripheral artery bypass only. Preoperative coronary angiography revealed CAD in 69.5% (n = 57) of patients. Patients with CAD were more likely to be older, hypertensive, and diabetic than patients without CAD (all p < 0.05). Preoperative electrocardiography showed that only 3/57 (5.3%) patients with CAD had ischemic heart disease. Of the 61 patients who underwent peripheral artery bypass, 27 (47.4%) underwent simultaneous CABG. Of the patients with CAD, 78.9% (45/57) required peripheral artery bypass, whereas 64.0% (16/25) of patients without CAD required peripheral artery bypass (p = 0.11). Comparing simultaneous CABG and peripheral artery bypass in PAD patients with CAD and isolated peripheral artery bypass in PAD patients regardless of CAD, the only significant difference was in operating time (362.00 +/- 79.18 vs. 246.55 +/- 79.15 min, p = 0.00). When compared with PAD patients with CAD who underwent isolated peripheral artery bypass, the results were similar. Two patients who had CAD and underwent isolated peripheral artery bypass died (p = 0.16). Patients with peripheral arterial obstructive disease should be examined for CAD using CAG, regardless of whether they have symptomatic ischemic heart disease, and simultaneous CABG and peripheral artery bypass is safe and feasible.

Comparison of myocardial loading between asynchronous pulsatile and nonpulsatile percutaneous extracorporeal life support.

We hypothesized that myocardial loading can be increased when extracorporeal pulse flow occurs during systole, and that this may adversely affect myocardial working conditions in heart failure patients supported by extracorporeal life support (ECLS). This study was designed to compare myocardial loading and myocardial oxygen consumption/supply balance between nonpulsatile ECLS and asynchronized pulsatile ECLS in a myocardial stunning model. Thirteen, 23-42 kg dogs were allotted to a nonpulsatile group and an asynchronous pulsatile group. Coronary sinus lactate level, mixed venous oxygen consumption (MvO2), and left anterior descending coronary artery flow were measured. The real-time pressure of the left ventricle and the ascending aorta was monitored, and the lowest left ventricular pressure and tension time index were calculated. Our results showed that the lactate level and the lowest left ventricular pressure were lower in the pulsatile group than in the nonpulsatile group at 30 minutes after ECLS was applicated (p < 0.05, respectively). Tension time index in the pulsatile ECLS group was substantially lower than in the nonpulsatile group. Left anterior descending coronary flow did not show significant difference between the two groups. In conclusion, asynchronous pulsatile ECLS may also be superior to nonpulsatile ECLS in myocardial volume unloading and oxygen consumption/supply balance.