Effect of inflow cannula side-hole number on drainage flow characteristics: flow dynamic analysis using numerical simulation.

BACKGROUND: Venous drainage in cardiopulmonary bypass is a very important factor for safe cardiac surgery. However, the ideal shape of venous drainage cannula has not been determined. In the present study, we evaluated the effect of side-hole number under fixed total area and venous drainage flow to elucidate the effect of increasing the side-hole numbers. METHOD: Computed simulation of venous drainage was performed. Cannulas were divided into six models: an end-hole model (EH) and models containing four (4SH), six (6SH), eight (8SH), 10 (10SH) or 12 side-holes (12SH). Total orifice area of the side-holes was fixed to 120 mm2 on each side-hole cannula. The end-hole orifice area was 36.3 mm2. The total area of the side-holes was kept constant when the number of side-holes was increased. RESULT: The mean venous drainage flow rate of the EH, 4SH, 6SH, 8SH, 10SH and 12SH was 2.57, 2.52, 2.51, 2.50, 2.49, 2.41 L/min, respectively. The mean flow rate decreased in accordance with the increased number of side-holes. CONCLUSION: We speculate that flow separation at the most proximal site of the side-hole induces stagnation of flow and induces energy loss. This flow separation may hamper the main stream from the end-hole inlet, which is most effective with low shear stress. The EH cannula was associated with the best flow rate and flow profile. However, by increasing side-hole numbers, flow separation occurs on each side-hole, resulting in more energy loss than the EH cannula and flow rate reduction.

Improved Outcomes for Ruptured Abdominal Aortic Aneurysms Using Integrated Management Involving Endovascular Clamping, Endovascular Replacement, and Open Abdominal Decompression.

Objective: Endovascular repair has become the treatment of choice for ruptured abdominal aortic aneurysms (RAAAs). To improve surgical outcomes, preoperative management is important. In 2011, we introduced integrated management, which involves endovascular aneurysm repair, stabilization of hemodynamics by endovascular clamping, and open abdominal decompression to address abdominal compartment syndrome (ACS). Methods: To evaluate the efficacy of this management strategy, 62 patients who had undergone emergency surgery for an RAAA were analyzed retrospectively: group A (n=39), where an old strategy was used, and group B (n=23), where integrated management was introduced. Patient characteristics and 30-day mortality rates were compared between the two groups. Results: The average patient age was 67.7 years and 74.7 years for groups A and B, respectively (P=0.032). Group B patients required more frequent use of vasopressors (P=0.035). Other patient characteristics did not differ between the two groups. The duration of surgery was significantly shorter in group B than in group A (P=0.001). The total amount of transfused blood did not differ between the two groups. No patients showed symptoms of ACS. Early mortality rates were 12.8% and 8.7% in groups A and B, respectively. The number of wound infections was significantly fewer in group B than in group A. Conclusion: Although group B patients were significantly older and had a higher rate of vasopressor use, early mortality was improved in both groups. Morbidity was significantly better in group B with respect to the duration of surgery and number of wound infections than in group A.

Surgical Management of Mycotic Aortic Aneurysms.

Purpose: A mycotic aneurysm is an uncommon disease associated with a high mortality rate when managed surgically. This study reviewed our experiences in the surgical management of mycotic aortic aneurysms. Methods: In total, 26 patients who underwent surgery for a mycotic aneurysm were retrospectively reviewed. The mycotic aneurysms involved the thoracic aorta in 9 patients, the thoracoabdominal aorta in 4 patients, and the abdominal aorta in 13 patients. An overt aortic rupture in the mediastinum or retroperitoneal space was detected in 4 patients. Patients were classified into one of two groups, febrile or afebrile, and background characteristics, surgical intervention, and early and late mortalities were all compared. Results: There were 19 patients who underwent open surgery, and 7 patients underwent endovascular repair. No significant differences in the clinical characteristics were found between the two groups; however, the incidence of postoperative complications was significantly higher in the febrile group than in the afebrile group (P=0.024). Overall mortality was 15.4% (4/26), and 30-day mortality was 7.7% (2/26). Conclusion: Although febrile patients had a higher incidence of postoperative complications, surgical mortality from a mycotic aneurysm was within an acceptable range. Each patient should be thoroughly evaluated and treated on a case-by-case basis, using conventional open repair, endovascular repair, or a combination of both approaches.

Successful Resuscitation of a Patient with Life-Threatening Metabolic Acidosis by Hemodialysis: A Case of Ethylene Glycol Intoxication.

BACKGROUND: Ethylene glycol intoxication causes severe metabolic acidosis and acute kidney injury. Fomepizole has become available as its antidote. Nevertheless, a prompt diagnosis is not easy because patients are often unconscious. Here we present a case of ethylene glycol intoxication who successfully recovered with prompt hemodialysis. CASE PRESENTATION: A 52-year-old Japanese male was admitted to a local hospital due to suspected food poisoning. The patient presented with nausea and vomiting, but his condition rapidly deteriorated, with worsening conscious level, respiratory distress requiring mechanical ventilation, hypotension, and severe acute kidney injury. He was transferred to the university hospital; hemodialysis was initiated because of hyperkalemia and severe metabolic acidosis. On recovering consciousness, he admitted having ingested antifreeze solution. Thirty-seven days after admission, the patient was discharged without requiring HD. CONCLUSIONS: We reported a case of ethylene glycol intoxication who presented with a life-threatening metabolic acidosis. In a state of severe circulatory shock requiring catecholamines, hemodialysis should be avoided, and continuous hemodiafiltration may be a preferred approach. However, one should be aware of the possibility of intoxication by unknown causes, and hemodialysis could be life-saving with its superior ability to remove toxic materials in such cases.

Management of deep vein thrombosis and pulmonary embolism (venous thromboembolism) during pregnancy.

PURPOSE: The risk of venous thromboembolism (VTE) is high during pregnancy. Although most patients with VTE are safely treated via medications, the optimal treatment for massive pulmonary embolism remains controversial. To evaluate the safety and efficacy of VTE management during pregnancy, we report our single center experience of treating VTE in pregnant women. METHODS: Case records were retrospectively reviewed from seven patients who underwent treatment for venous thromboembolism between 2002 and 2014. RESULTS: Mean gestational time was 28 ± 6.2 weeks. Four patients with deep vein thrombosis were treated medically, and they all had vaginal delivery at full term without hemorrhagic complication. Three patients with massive pulmonary embolism underwent surgical embolectomy. Two of these three patients underwent cesarean delivery at 28 and 29 weeks respectively. There was no maternal death, but one fetal death occurred during surgical embolectomy. CONCLUSION: VTE during pregnant women is safely managed by anticoagulant therapy. Massive pulmonary embolism during pregnancy can be managed safely by surgical embolectomy using cardiopulmonary bypass, but the rate of fetal loss remains high.

[Surgery for Infective Endocarditis Involving Valve Annulus].

Surgical treatment for isolated infective endocarditis( IE) has been improving over the last 2 decades. However, surgery for complicated IE such as disruption of paravalvular structure remains a challenge. The aim of this retrospective study is to evaluate our surgical results for IE with paravalvular structural disruption. From January 2002 to March 2015, we performed cardiac surgery for 68 patients who suffered from IE. Thirteen patients had paravalvular abscess and fistula. Valve disruptions were seen in aortic valve in 10 patients [2 fistulas from right coronary cuspid to right atrium or ventricle, 3 abscess formation from right coronary cuspid to interventricular septum, 1 abscess formation from left coronary cuspid to anterior mitral leaflet, 1 left ventricle to right atrium communication from non-coronary cuspid (NCC), 2 abscess formation under NCC and 1 circular annulas infection]. Mitral valve involvement was found in 2 patients [1 posterior mitral leaflet (PML) infection and submitral abscess infiltrating to annula calcification and 1 PML infection with submitral abscess]. One patient who had tricuspid valve involvement had giant vegetation from tricuspid to pulmonary valve through right ventricular outflow tract. Radical debridement of infected tissue and reconstruction using allograft, artificial valve and conduit were performed in all cases.

[Management of Infective Endocarditis with Neurological Complication].

Neurological complications in patients with infective endocarditis are frequent and mortality is higher in those with neurological complications than in those without. The spectrum of neurological complications includes cerebral infarction, intracranial hemorrhage, intracranial infectious aneurysm, transient ischemic attack (TIA), meningitis, encephalopathy and brain abscess. The appropriate timing of valve surgery following a cerebrovascular event remains controversial because cardiopulmonary bypass may exacerbate neurological deficits. Previous studies suggest delaying valve surgery for 2 to 4 weeks following embolic stroke and at least 4 weeks following hemorrhagic stroke however, urgent valve surgery may be needed depending on the hemodynamic state of the patient. In the event of intracranial infectious aneurysm, therapeutic management is not perfectly standardized. We retrospectively reviewed the surgical results of infective endocarditis patients with neurological complications. Current trends in surgical timing and therapeutic decision-making are discussed.

Acute limb ischemia: contemporary approach.

Acute limb ischemia is a critical condition with high mortality and morbidity even after surgical or endovascular intervention. Early recognition is important, but a delayed presentation is not uncommon. Viability of the limb is assessed by motor and sensory function and with interrogating Doppler flow signals in pedal arteries and popliteal veins as categorized by Rutherford. Category IIa indicates mild-to-moderate threat to limb salvage over a time frame without revascularization. Limb ischemia is critical without prompt revascularization in category IIb. Because the risk of reperfusion injury is high in this group of patients, perioperative management is important. In category III, reperfusion is not indicated except for embolism within several hours of onset. Intimal injury should be avoided by careful tactile control of a balloon with a smaller size catheter and under radiographic monitoring. Adjunctive treatment with catheter-directed thrombolysis or bypass surgery is sometimes necessary. Endovascular treatment is a promising option for thrombotic occlusion of an atherosclerotic artery. Ischemia-reperfusion injury is a serious problem. Controlled reperfusion with low-pressure perfusion at a reduced temperature and use of a leukocyte filter should be considered. The initial reperfusate is hyperosmolar, hypocalcemic, slightly alkaline, and contains free radical scavengers such as allopurinol. Immediate hemodialysis is necessary for acute renal injury caused by myoglobinemia. Compartment syndrome should be managed with assessment of intra-compartment pressure and fasciotomy.

Management of infective endocarditis with cerebral complications.

PURPOSE: Management of patients with infective endocarditis complicated by neurological deficits is challenging. No clear management guidelines have been defined, and the timing of surgery remains controversial. The purpose of this study was to evaluate our management algorithm. METHODS: Thirty-eight adult patients with left-sided infective endocarditis undergoing valve surgery were analyzed. Before the operation, enhanced brain computed tomography (CT) was performed to rule out a cerebral complication. Pre and postoperative data were retrospectively reviewed to clarify whether our algorithm was effective. Sixteen patients having neurological complication (CVC group) were compared with 22 patients without neurological complication. RESULTS: Age, sex, New York Heart Association (NYHA) functional class, affected valve and pathogens were not different between two groups. Mean interval from the onset of neurological dysfunction to cardiac operation was 27.8 ± 27.8 days (median 23 days). Of the 16 CVC group patients, 12 experienced cerebral infarction. Mass effects were seen in 3 patients, with 1 of these 3 patients died following aneurysm rupture. Mycotic aneurysm was detected in 4 patients, with 3 undergoing successful staged operations. Mortality and postoperative neurological exacerbation in CVC group was 6.3% (1 patient). Most patients who fulfilled the algorithm showed good outcomes. CONCLUSIONS: Our suggested management algorithm for infective endocarditis appears effective.

Shaggy and calcified aorta: surgical implications.

Atheroembolism is an emerging problem in cardiovascular surgery, especially in elderly patients. Severe atherosclerosis of the thoracic aorta usually reflects systemic atherosclerosis. Aggressive preoperative and intraoperative evaluation of the aorta using enhanced CT, transesophageal echocardiography and epiaortic ultrasound is important in elderly patients as well as those with systemic atherosclerosis. To prevent atheroembolism, it is important to select an adequate arterial perfusion site and to avoid touching the diseased aorta until circulatory arrest. In atherosclerotic aortic arch aneurysm, central cannulation under ultrasound guidance and directing the dispersive cannula toward the aortic root is a simple and effective perfusion strategy. Axillary perfusion is useful as an alternative to central cannulation in atherosclerotic aortic disease, but special care is necessary to avoid complications when the patient has a small axillary artery or flail atheroma around the arch vessels. In femoral artery perfusion, retrograde perfusion may induce paradoxical cerebral embolism, but the incidence of stroke is comparable with axillary perfusion when there is adequate preoperative screening using transesophageal echography. Circulatory arrest with/without cerebral perfusion is another important strategy when the aorta has severe atherosclerosis. Recent literature has shown that mild hypothermia may be safe for anterior cerebral perfusion during circulatory arrest, but optimal flow rates and time limitations are unknown. A simple calcified aorta called "porcelain aorta" may be managed by circulatory arrest, local debridement and the clamp method. Several surgical options are proposed for this clinical entity but their use will diminish in the future because of transcatheter valve replacement.

Screw in the aorta: minimally invasive graft replacement for chronic aortic erosion by spinal instrument.

Intra-and early post-operative aortic injury by pedicle screw is not a rare complication in orthopedic surgery, but aortic penetration by a screw head over a long time period is considered as an uncommon case. There are various surgical management options for thoracic aortic injury caused by malpositioned spinal instruments. We report a case of a patient who underwent minimally invasive graft replacement of the descending thoracic artery for pedicle screw penetration.

Leiomyosarcoma of the external iliac vein.

Leiomyosarcoma of the iliac vein is an uncommon tumor. We report a case of a 63-year-old Japanese woman with leiomyosarcoma of the right external iliac vein. The patient complained of right inguinal pain and swelling. Computed tomography demonstrated a mass surrounding the right external iliac artery and vein. Metastases in the lungs and liver were found. Complete resection of the tumor along with the involved vessels was performed. Polytetrafluoroethylene grafts were used to reconstruct the vessels. Pathological examination revealed leiomyosarcoma of the external iliac vein. Although the prognosis of leiomyosarcoma is poor, en bloc tumor resection is the treatment of choice.

Outcome of pulmonary embolectomy for acute pulmonary thromboembolism: analysis of 32 patients from a multicentre registry in Japan.

OBJECTIVE: Massive pulmonary embolism is relatively rare but a potentially life-threatening condition. The purpose of this study was to analyse the outcome of pulmonary embolectomy in registered data from the Japanese Society of Pulmonary Embolism Research (JaSPER). METHODS: From 1994 to 2006, 1661 cases of acute pulmonary embolism were registered in the JaSPER database. Retrospective analysis of 32 patients undergoing pulmonary embolectomy was conducted. The overall incidence of pulmonary embolectomy was 1.9% [95% confidence interval (CI): 1.8-3.2%]. The mean age of patients was 57 years and 66% were female. RESULTS: Overall mortality of pulmonary embolectomy was 18.8% [95% CI: 5.2-25.6%]. Most of the patients had massive or submassive pulmonary thromboembolism, and three patients experienced cardiopulmonary arrest before embolectomy. Ten patients received preoperative percutaneous cardiopulmonary bypass, and mortality was 30% in this subgroup. CONCLUSIONS: Pulmonary embolectomy is an effective therapeutic option for patients with massive or submassive pulmonary embolism. Prompt triage of patients with haemodynamic instability is important.

Infective endocarditis with cerebrovascular complications: timing of surgical intervention.

Management of infective endocarditis (IE) with cerebrovascular complications is difficult due to absence of concrete evidence. These patients usually have multiple neurological deficits and the optimal timing for cardiac operation remains controversial. The aims of this study were to present cases and discuss the treatment options for IE with cerebrovascular complications. From 1998 to 2010, 51 patients underwent operations for IE at our institution. From a review of medical records, 10 patients (19.6%) with preoperative neurological complications were identified. Data on these 10 patients were analysed. Cerebrovascular complications included cerebral infarction (n = 4, 40.0%), mycotic aneurysm (n = 1, 10.0%), mycotic aneurysm plus cerebral infarction (n = 3, 30.0%), meningitis (n = 1, 10.0%) and mycotic aneurysm with cerebral haemorrhage plus meningitis (n = 1, 10.0%). Of 5 patients having mycotic aneurysms, 3 underwent clipping before cardiac operations. The mean interval from craniotomy to cardiac operations was 26.7 ± 21.8 days. A cardiac operation was performed initially on seven patients. The mean interval from the onset of neurological deficit to cardiac operation was 7.4 ± 9.8 days. The mortality rate was 10.0%. Postoperative deterioration was not observed. Management of IE with cerebrovascular complications should be based on case-by-case multidisciplinary assessment of potential risks and benefits of intracranial and cardiac operations.

Endovascular treatment of ruptured intercostal arteriovenous fistulas associated with neurofibromatosis type 1.

Wereport a rare case of ruptured intercostal arteriovenous fistula in a patient with neurofibromatosis type 1. The patient presented with severe back pain. Angiography revealed ruptured intercostal arteriovenous fistulas. Successful coil embolization to occlude the fistulas and the aneurysm resulted in successful recovery of the patient.

Intimal sarcoma of the pulmonary artery--diagnostic challenge.

Pulmonary artery intimal sarcoma is a rare tumour and the diagnosis is often delayed. We report the case of a woman with a primary pulmonary artery intimal sarcoma who presented with massive pulmonary embolism. The definitive diagnosis was elucidated after the patient's death by autopsy specimen. We discuss the diagnosis and lessons learned from this case.

Vacuum-assisted venous drainage in tricuspid valve re-replacement.

The number of reoperations for prosthetic valve replacement has increased in recent years due to the steady increase in life expectancy. However, reoperations are complex and require experience and skills. We report the case of a 69-year-old female with severe right heart failure who underwent tricuspid valve re-replacement 28 years after the initial tricuspid valve replacement. Cardiopulmonary bypass with vacuum-assisted venous drainage (VAVD) was used to achieve better perfusion flow and heart decompression with smaller venous cannulae. The operation was successful. The VAVD system is effective in patients who have a persistent elevation of central venous pressure.