Mitsuhiro Yano

Adventitial Mast Cells Contribute to Pathogenesis in the Progression of Abdominal Aortic Aneurysm

Abdominal aortic aneurysm (AAA) is histologically characterized by medial degeneration and various degrees of chronic adventitial inflammation, although the mechanisms for progression of aneurysm are poorly understood. In the present study, we carried out histological study of AAA tissues of patients, and interventional animal and cell culture experiments to investigate a role of mast cells in the pathogenesis of AAA. The number of mast cells was found to increase in the outer media or adventitia of human AAA, showing a positive correlation between the cell number and the AAA diameter. Aneurysmal dilatation of the aorta was seen in the control (+/+) rats following periaortic application of calcium chloride (CaCl2) treatment but not in the mast cell–deficient mutant Ws/Ws rats. The AAA formation was accompanied by accumulation of mast cells, T lymphocytes and by activated matrix metalloproteinase 9, reduced elastin levels and augmented angiogenesis in the aortic tissue, but these changes were much less in the Ws/Ws rats than in the controls. Similarly, mast cells were accumulated and activated at the adventitia of aneurysmal aorta in the apolipoprotein E–deficient mice. The pharmacological intervention with the tranilast, an inhibitor of mast cell degranulation, attenuated AAA development in these rodent models. In the cell culture experiment, a mast cell directly augmented matrix metalloproteinase 9 activity produced by the monocyte/macrophage. Collectively, these data suggest that adventitial mast cells play a critical role in the progression of AAA.

Clinical Implications of Additional Pedal Artery Angioplasty in Critical Limb Ischemia Patients With Infrapopliteal and Pedal Artery Disease.

Purpose: To evaluate the clinical implications of additional pedal artery angioplasty (PAA) for patients with critical limb ischemia (CLI). Methods: Twenty-nine patients (mean age 77.8±8.6 years; 21 men) with CLI (32 limbs) presenting with de novo infrapopliteal and pedal artery (Kawarada type 2/3) disease were reviewed. The need for PAA was based on the existence of sufficient wound blush (WB) around the target wounds after conventional above-the-ankle revascularization. Fourteen patients with insufficient WB in 14 limbs received additional PAA, while 15 patients with sufficient WB in 18 limbs did not. The groups were compared for overall survival, limb salvage, and amputation-free survival within 1 year after the procedure. The wound healing rate, time to wound healing, and freedom from reintervention rate were also evaluated. Result: The success rate of additional PAA was 93% (13/14). All limbs with successful PAA achieved sufficient WB (13/13). Despite insufficient WB before the additional PAA, overall survival (86% vs 73%, p=0.350), limb salvage (93% vs 83%, p=0.400), amputation-free survival (79% vs 53%, p=0.102), and freedom from reintervention (64% vs 73%, p=0.668) rates were similar in both groups. Furthermore, the wound healing rate (93% vs 60%, p=0.05) was higher and time to wound healing (86.0±18.7 vs 152.0±60.2 days, p=0.05) was shorter in the patients who received PAA. Conclusion: Additional PAA might improve the WB and clinical outcomes (especially speed and extent of wound healing) in patients with CLI attributed to infrapopliteal and pedal artery disease.

Efficacy and Safety of a Percutaneous Right Ventricular Assist System

BACKGROUND Mechanical right ventricular assistance is necessary in the management of profound right ventricular failure resistant to medical therapy. Conventional right ventricular assistance requires a thoracotomy. We developed a technique for assisting the failing right ventricle without thoracotomy. METHODS We implanted the percutaneous right ventricular assist system in animals to test its feasibility and safety. A feasibility study was performed in a right ventricular failure model using 12 open chest dogs, and we examined the effects of the system hemodynamically. Next, the system was implanted into 6 goats and driven for 2 to 8 days. RESULTS Institution of the percutaneous right ventricular assist system revealed overall hemodynamic improvement on right ventricular failure in dogs. In the goat experiment, no animal died from cannula-related complications. No damage to the intracardiac structures and no pulmonary edema were seen. Plasma free hemoglobin concentration did not exceed 10 mg/dL. CONCLUSIONS The percutaneous right ventricular assist system is safe and effective in the management of right ventricular failure.

Mycotic pseudoaneurysm of the ascending aorta caused by Escherichia coli

An 81-year old woman with high fever and a history of hospital admission because of pyelonephritis 3 months previously was transferred to our hospital. Contrast-enhanced computed tomography revealed a mycotic pseudoaneurysm in the ascending aorta and a massive pericardial effusion. We resected the ascending aorta and the proximal part of the brachiocephalic artery and performed in situ revascularization with a prosthetic vascular graft. Bacterial examination proved that the causative micro-organism was Escherichia coli. The prosthetic graft was wrapped with a pedicled omentum following completion of the aortic reconstruction. Her postoperative course was uneventful. She was discharged from the hospital 1 month postoperatively.

Surgical resection of right atrial neurilemoma extending to pulmonary vein.

An asymptomatic cardiac neurilemoma was found in a 33-year-old woman. The tumor was on the anterior surface of the right atrium extending to the right upper pulmonary vein across the interatrial groove. The tumor was resected completely and right atrium, interatrial septum, left atrium and right superior pulmonary vein were reconstructed with cardiopulmonary bypass. The patient recovered uneventfully and had no recurrence 1 year after the operation. We reviewed ten reported cases of cardiac neurilemoma, including our patient.

Nafamostat mesilate treatment during open heart operation in immune thrombocytopenic purpura

A 58-year old woman with idiopathic thrombocytopenic purpura underwent mitral and aortic valve replacements and tricuspid annuloplasty. Preoperative therapeutic interventions including prednisone and immunoglobulin were successful in elevating the platelet count to 93,000/ mm2. Furthermore, we used nafamostat mesilate for coagulopathy prophylaxis during cardiopulmonary bypass. Postoperative bleeding was average and clinical course was uneventful. The perioperative management for patients with idiopathic thrombocytopenic purpura requiring cardiac operation is reviewed.

Recurrent upper limb ischaemia due to a crutch-induced brachial artery aneurysm.

An 83-year old man who had used bilateral axillary crutches for 67 years was referred to our hospital for acute left upper limb ischaemia. He underwent successful recanalization through emergent catheter thromboembolectomy. However, a crutch-induced left brachial artery aneurysm was subsequently detected by computed tomography. Therefore, we performed aneurysm exclusion and subsequent saphenous vein bypass grafting. When a crutch user presents with upper limb ischaemia, a high index of suspicion and early identification of the crutch induced vascular injury are mandatory for appropriate treatment.

Open surgery or stent repair for descending aortic diseases: Results and risk factor analysis

Objectives. Less invasive stent graft (SG) repair was compared with open surgery for patients with descending thoracic aortic diseases. Design. Thirty six patients undergoing SG repair (SG group) were matched for age, sex, location and pathology of aortic disease with a 36-patient surgical cohort (OS group), and retrospective matched case-control study was performed with respect to outcomes and risk factors for adverse outcomes. Results. Mortality rate was 5.6% in OS group and none in SG group (p=0.4930), and there was no significant difference in stroke and paraplegia rates between two groups. A higher prevalence of secondary procedures due to endoleak was seen in the patients of SG group (p=0.0113). Perioperative hypotension was an independent risk factor for in-hospital mortality (p=0.0071, odds ratio=34) and preoperative renal dysfunction was independent risk factor for paraplegia (p=0.0076, odds ratio=17.6). Conclusions. Although the importance of patient selection is emphasized to prevent endoleak, mortality rate was low in patients who underwent SG repair. SG repair is a promising alternative technique to open surgery for thoracic aortic diseases.

Emergent Completion Pneumonectomy for Postoperative Hemorrhage from Rupture of the Infected Pulmonary Artery in Lung Cancer Surgery

Completion pneumonectomy (CP) is one of the most difficult procedures and known to be associated with a high morbidity and mortality. A 74-year-old male underwent a left upper lobectomy for pulmonary adenocarcinoma (T3N0M0); six days later after the surgery, he had a sudden postoperative intrathoracic excessive hemorrhage with shock. Emergent redo thoracotomy was performed to treat the bleeding from the ablated interlobar pulmonary artery by suturing with prolene. However, 3 days later after the second operation, he had the second intrathoracic bleeding. Emergent CP was performed with cardiopulmonary bypass by anterior transpericarsial approach via a median sternotomy. The hemorrhage was caused by a rupture of the proximal fragile and infected pulmonary artery. We performed omentopexy for the infected intrathoracic cavity and for covering of the divided main bronchial stump. We had a rare experience of two times of postoperative life-threatening hemorrhage from rupture of the infected pulmonary artery after left upper lobectomy. Emergent CP as salvage surgery should have an advantage in control of infected proximal pulmonary arterial hemorrhage. We should take care of tearing off of adventitia of pulmonary artery in lobectomy because of a possibility of postoperative hemorrhage under a fragility of the injured pulmonary artery with infection.

Predictor of neurologic dysfunction after elective thoracic aorta repair using selective cerebral perfusion.

Objectives This study was undertaken to determine the factors that influence postoperative neurological dysfunction after selective cerebral perfusion (SCP). Design From 1995 to August 2004, 60 patients were evaluated for the presence of cerebro-vascular disease (CVD), and then underwent thoracic aortic operations using SCP. Perioperative factors were evaluated by multivariate analyses. Results Hospital mortality rate was zero. Sixteen patients (26.7%) proved to have CVD. Permanent neurological dysfunction (PND) appeared in three patients (5.0%) and transient neurological dysfunction (TND) in two (3.3%). Univariate analysis revealed superficial temporal artery (STA) pressure during SCP (p=0.0410) to be a significant risk factor for PND. Variables that achieved values of p<0.2 (aortic cross-clamp time, presence of CVD, old cerebral infarction, presence of clots or atheroma) were examined with multivariate analysis and the presence of CVD (p=0.038) and STA pressure during SCP (p=0.032) were independent risk factors for PND. Multivariate analysis for TND did not show any risk factor. Conclusions The presence of CVD was indicated as an independent risk factor for PND after thoracic aortic operations using SCP.