Kenji Okada

Simple left atrial procedure for chronic atrial fibrillation associated with mitral valve disease

BACKGROUND A computerized 48-channel mapping system was used to investigate the characteristics of an atrial epicardial electrogram during chronic atrial fibrillation (AF) in patients with solitary mitral valve disease. We have devised a simple left atrial procedure to eliminate the chronic AF during a mitral valve operation. METHODS Using this mapping system, we performed intraoperative atrial mapping in 11 patients with chronic AF associated with mitral valve disease. The AF duration ranged from 0.4 to 15 years (mean, 8.0 +/- 4.5 years). A simple surgical ablation of the AF on the left atrium only was performed during the mitral valve operations. RESULTS The mean AF cycle length of the atria ranged from 129 to 169 milliseconds in the right atrium and from 114 to 139 milliseconds in the left atrium. The mean AF cycle length of the left atrium was shorter than that of the right atrium. Regular and repetitive activation was found in the left atria of 7 of 11 patients. The AF disappeared in all patients immediately after the operation, and 10 of these patients continued to have a sinus rhythm postoperatively (AF-free rate, 91%). CONCLUSIONS Computerized intraoperative mapping revealed a shorter mean AF cycle length in the left atrium. A simple left atrial procedure was effective in eliminating chronic AF associated with solitary mitral valve disease.

Efficacy of a simple left atrial procedure for chronic atrial fibrillation in mitral valve operations.

BACKGROUND We have devised a simple surgical procedure to be performed on the posterior wall of the left atrium for the treatment of chronic atrial fibrillation (AF) associated with mitral valve disease. The effectiveness of this procedure for serial mitral valve operations was then evaluated. We postulated that chronic AF associated with mitral valve disease could be attributable to a distended left atrium. The refractory period of the distended left atrium was significantly shorter in the left posterior atrial wall, especially at the base of the left atrial appendage and at the orifice of the left posterior pulmonary vein. We hypothesized that the left posterior atrial wall with its shorter fibrillatory cycle length would act as a driver for maintaining the AF, and therefore, surgical ablation of this critical area in the left atrium could terminate the chronic AF. METHODS The surgical patients were divided into two groups. In group 1 (control group), 15 patients with chronic AF were operated on by the mitral valve procedure only. In group 2, 36 patients underwent this procedure in combination with a concomitant mitral valve operation. The disappearance rate of the AF was estimated by electrocardiography, and atrial function was estimated by transthoracic and transesophageal echocardiography. RESULTS The chronic AF had been reduced significantly or eliminated at discharge in 4 of 15 patients (26.7%) in the group 1, versus 31 of 36 patients (86%) in group 2 (p < 0.05). In group 2, 29 of the 31 patients (94%) whose AF had disappeared recovered the atrial kick of their right atrium, and 21 patients (22/31; 71%) recovered the atrial kick of their left atrium. CONCLUSIONS Surgical ablation of the posterior wall of the left atrium was effective in the treatment of chronic AF associated with mitral valve disease. This simple procedure could restore a sinus rhythm and also recovered atrial systolic function. We conclude that the left atrium may act as a driver for sustaining AF in mitral valve disease.

Efficacy of pulmonary vein isolation for the elimination of chronic atrial fibrillation in cardiac valvular surgery

BACKGROUND Haissaguerre and colleagues emphasize the importance of the pulmonary veins as a source of ectopic foci for initiating paroxysmal atrial fibrillation (AF). We hypothesized that ectopic foci from the pulmonary veins could also act as drivers for maintaining chronic AF, and that surgical ablation of the pulmonary vein orifices could terminate chronic AF. METHODS Using a computerized 48-channel mapping system, we performed intraoperative atrial mapping in 12 patients with chronic AF associated with mitral valve disease. Patient age ranged from 24 to 82 years (mean, 60.4 years). AF duration ranged from 3 to 240 months (mean, 92+/-84 months). Simple surgical isolation of the pulmonary vein orifices was performed during the mitral valve operation. RESULTS Regular and repetitive activation was found in the left atria of 9 out of 12 patients, and irregular and chaotic activation was found in both atria of 3 out of 12 patients. Chronic AF in the 9 patients (75%) with regular and repetitive activation of their left atria was successfully treated by a simple surgical isolation of the pulmonary vein orifices. The other 3 patients did not recover sinus rhythm after this procedure. In 1 case of recurrent AF, the patient recovered sinus rhythm during the follow-up period (AF-free rate, 83%). CONCLUSIONS Surgical ablation of the pulmonary vein orifices was effective in the treatment of chronic AF associated with mitral valve disease. Intraoperative mapping may be useful in predicting the efficacy of a single pulmonary vein orifice isolation procedure.

Sodium 4-phenylbutyrate protects against spinal cord ischemia by inhibition of endoplasmic reticulum stress.

OBJECTIVE Delayed paraplegia after operation on the thoracoabdominal aorta is considered to be related to vulnerability of motor neurons to ischemia. Previous studies have demonstrated the relationship between neuronal vulnerability and endoplasmic reticulum (ER) stress after transient ischemia in the spinal cord. The aim of this study was to investigate whether sodium 4-phenylbutyrate (PBA), a chemical chaperone that reduces the load of mutant or unfolded proteins retained in the ER during cellular stress, can protect against ischemic spinal cord damage. METHODS Spinal cord ischemia was induced in rabbits by direct aortic cross-clamping (below the renal artery and above the bifurcation) for 15 minutes at normothermia. Group A (n = 6) was a sham operation control group. In group B (n = 6) and group C (n = 6), vehicle or 15 mg/kg/h of sodium 4-PBA was infused intravenously, respectively, from 30 minutes before the induction of ischemia until 30 minutes after reperfusion. Neurologic function was assessed at 8 hours, and 2 and 7 days after reperfusion with a Tarlov score. Histologic changes were studied with hematoxylin-eosin staining. Immunohistochemistry analysis for ER stress-related molecules, including caspase12 and GRP78 were examined. RESULTS The mean Tarlov scores were 4.0 in every group at 8 hours, but were 4.0, 2.5, and 3.9 at 2 days; and 4.0, 0.7, and 4.0 at 7 days in groups A, B, and C, respectively. The numbers of intact motor neurons at 7 days after reperfusion were 47.4, 21.5, and 44.9 in groups A, B, and C, respectively. There was no significant difference in terms of viable neurons between groups A and C. Caspase12 and GRP78 immunoreactivities were induced in motor neurons in group B, whereas they were not observed in groups A and C. CONCLUSION Reduction in ER stress-induced spinal cord injury was achieved by the administration of 4-PBA. 4-PBA may be a strong candidate for use as a therapeutic agent in the treatment of ischemic spinal cord injury.

Endovascular stent-grafting via the aortic arch for distal aortic arch aneurysm : an alternative to endovascular stent-grafting

OBJECTIVE We have experienced transaortic stent-grafting for treating distal arch aneurysm or type B dissection. This paper is to mainly report the surgical aspect of these procedures. METHODS Fifteen patients underwent this surgery, including 12 men and three women ranging from 47 to 83 years. Twelve had aneurysms and three aortic dissection. Concomitant surgery was necessary in seven patients (coronary artery bypass grafting in five, tricuspid annuloplasty in one, and replacement of ascending aorta and/or total arch replacement in three cases). A stent graft (Gianturco Z-stent and Intervascular prosthesis) was loaded in a 30-F sheath catheter. Under circulatory arrest, selective cerebral perfusion was established, and the sheath catheter was inserted through aortotomy into descending aorta and the stent graft was deployed at an appropriate level. The proximal end of graft was sutured to the aorta just distal to the left subclavian artery with inclusion method at the posterior wall. Concomitant surgery was done during cooling or rewarming period. TEE was utilized to visualize every endovascular manipulation to avoid unintended intimal injury or misplacement of graft and to assess the surgical results in the operative theater. RESULTS Aneurysm was successfully excluded except in one patient who had a proximal endoleak and distal endoleak due to underestimation of aortic diameter. There was one operative mortality caused by cerebral infarction, possibly due to debris from femoral arterial cannulation. In the remaining patients, there was no enlargement of residual aneurysm. The excluded aneurysmal sac gradually regressed and disappeared within 2 years in five patients and the thrombosed false lumen completely shrunk within 1 year in two patients. One patient had paraplegia, possibly because the graft was intentionally advanced deeply to cover the thick and fragile atheromatous layer in order to avoid destruction of the atheroma by an expanded graft. CONCLUSIONS Endovascular stent graft via the aortic arch is an acceptable treatment for distal arch aneurysms close to or involving left subclavian artery or type B dissections, especially for those cases requiring other cardiac procedures. It can lead to regression and disappearance of aneurysm or dissection in the mid-term follow-up.

Endovascular stent-grafting through the aortic arch: an alternative approach for distal arch aortic aneurysm

BACKGROUND Endovascular stent-grafting is an innovative procedure; we have developed a novel approach to treat distal arch aortic aneurysm through a small incision in the aortic arch. METHODS Eight patients with thoracic aortic aneurysms were treated with an endovascular stent-graft that was introduced into the thoracic aorta through a small incision in the aortic arch. Of these patients, 7 had distal arch aortic aneurysms, and 1 had chronic aortic dissection of Stanford type B. Four of these patients had received concomitant coronary artery bypass grafting, and 1 patient had undergone tricuspid valvular annuloplasty. The stent-graft was introduced into the distal arch aorta and descending aorta through a small incision in the aortic arch, under selective cerebral perfusion and hypothermic circulatory arrest. RESULTS The selective cerebral perfusion time ranged from 52 to 86 minutes (mean, 68 minutes) and the operating time from 289 to 422 minutes (mean, 318 minutes). There was no endoluminal leakage into the aneurysm. Seven patients survived and were discharged, but 1 patient suffered a cerebral infarction and died during the follow-up period. CONCLUSIONS Placing an endovascular stent-graft through the aortic arch is an acceptable alternative treatment for distal arch aortic aneurysms.

Successful Coil Embolization for Spontaneous Arterial Rupture in Association with Ehlers-Danlos Syndrome Type IV: Report of a Case

When a patient with Ehlers-Danlos syndrome (EDS) presents with a vascular emergency, performing life-saving surgery can be difficult because of the profound fragility of the arterial tissue. We report the case of a 27-year-old woman with EDS in whom a spontaneous arterial rupture was successfully treated with transcatheter embolization. The patient was brought to our hospital in shock, with left lower abdominal pain. She had been diagnosed with EDS type IV following a colonic rupture 8 years earlier. An emergency angiogram revealed rupture of the left external iliac artery. The active bleeding was managed by transarterial embolization of the ruptured artery using stainless steel coils, which took 30 min to achieve. The patient has not suffered any further vascular complications during the year since this procedure. Transcatheter coil embolization may be a reliable option for treating sudden arterial rupture in patients with this syndrome.

Compressed true lumen in the innominate artery: A pitfall of right axillary arterial perfusion in acute aortic dissection

Although axillary arterial perfusion (AX-P) is often preferred to femoral arterial perfusion (FA-P) in acute aortic dissection because it is associated with a lower incidence of malperfusion, it is unlikely to be perfect. We used near-infrared spectroscopy and orbital Doppler to detect cerebral malperfusion and transesophageal echocardiography (TEE) to clarify the malperfusion mechanism and observed a case of malperfusion after bilateral AX-P, which was relieved after interruption of the right AX-P. We report another case of malperfusion after right AX-P resulting from the narrowing of the innominate artery (IA) lumen.

Cold Blood Spinal Cord Plegia For Prediction of Spinal Cord Ischemia During Thoracoabdominal Aneurysm Repair

BACKGROUND This clinical study was undertaken to evaluate changes in motor evoked potentials (MEPs) during cold blood infusion into a thoracoabdominal aortic aneurysm. We also determined the efficacy of this infusion method for predicting spinal cord injury during thoracoabdominal aortic aneurysmal surgery. METHODS We monitored descending evoked spinal cord potentials (ESCPs), segmental ESCPs, and MEPs during the prosthetic replacement phase of thoracoabdominal aneurysmal surgery. We perfused cold blood (4 degrees C, 300 to 450 mL) into aneurysms after clamping the aorta, while monitoring spinal cord potentials in 6 cases of thoracoabdominal aortic aneurysm. If the spinal cord potentials decreased during infusion of cold blood, we reconstructed the intercostal arteries in the aneurysm. If the potentials did not change during the infusion of cold blood and after the aneurysmectomy, we did not reconstruct the intercostal arteries and ligated all of them. RESULTS Postoperative paraplegia did not occur in any case. The MEPs decreased in amplitude after infusion of cold blood in 3 cases, but amplitude recovered after reconstruction of the intercostal arteries. The other 3 cases did not show any change after infusion of cold blood, and all of the intercostal arteries in the aneurysm were ligated. CONCLUSIONS Cold blood infusion into the aneurysm while monitoring MEPs was a useful adjunct to detect the presence of critical intercostal arteries and to facilitate thoracoabdominal aortic aneurysmal surgery.

Fate of aneurysms of the distal arch and proximal descending thoracic aorta after transaortic endovascular Stent-Grafting

BACKGROUND The purpose of this study was to evaluate the midterm results of transaortic stent-grafting for distal aortic arch aneurysms or proximal descending aortic aneurysms and the feasibility of this method for thoracic aortic aneurysm repair. METHODS Twenty-three patients with true distal aortic arch aneurysms or proximal descending thoracic aortic aneurysms were repaired with the stent-graft introduced through the incision on the proximal arch aorta. Follow-up computed tomography was performed every 6 months in 21 surviving patients. The maximum dimension of the excluded aneurysmal space and the maximum aneurysmal diameter were measured and evaluated to determine whether the aneurysmal space decreased or disappeared after this alternative procedure. RESULTS There was 1 hospital death (4.3%) due to cerebral embolism. Another patient died of pneumonia 1 year after surgery. Twenty-one patients (91%) survived during the follow-up period, but 1 patient (4.3%) suffered from paraplegia. The follow-up period ranged from 12 to 62 months (average, 34.3 +/- 15.2). There were no instances of aneurysmal rupture during the follow-up period. Postoperative serial computed tomography scans showed disappearance or significant shrinkage of the excluded aneurysmal space in 20 of 21 patients (95%), except for the one patient with endoluminal leakage. CONCLUSIONS Transaortic endovascular stent-grafting was an effective alternative approach to treating distal aortic arch aneurysms or proximal descending aortic aneurysms. The excluded aneurysm disappeared or shrunk after successful placement of the stent-graft.