Taiichi Takasaki

Multiple factors predict the risk of spinal cord injury after the frozen elephant trunk technique for extended thoracic aortic disease

OBJECTIVES Spinal cord injury (SCI) after the frozen elephant trunk (FET) technique is more frequent than after endovascular aneurysm repair. This study aimed to identify risk factors of SCI after the FET technique. METHODS We performed the FET technique for extended thoracic aortic disease in 224 patients (mean age, 72.1 ± 10.9 years) from September 1997 to December 2011. The patients included those with acute type A aortic dissection (n = 103), acute type B aortic dissection (n = 30), chronic type B aortic dissection (n = 11) and thoracic atherosclerotic aneurysm (n = 80). Cerebrospinal fluid drainage (CSFD) was preoperatively performed for 18 elective cases with a high risk of spinal cord ischaemia from January 2003. RESULTS Postoperative SCI was present in 8 (3.5%), including complete paraplegia in 3, patients and transient or permanent paraparesis in 5 patients. CSFD was not a significant independent risk factor (P = 0.93) for SCI. Univariate logistic regression analysis identified pathology (P = 0.001), diabetes (P = 0.001), previous aortic operation (P = 0.003), atherosclerotic aorta (P = 0.003), distal position of the stent graft below the ninth thoracic vertebral level (Th9; P = 0.001) and low blood pressure after the operation (P = 0.009) as significant independent risk factors for SCI. Stepwise logistic regression analysis identified the distal position of the stent graft below Th9 (P = 0.003; odds ratio [OR], 15.167; 95% confidence interval [95% CI], 2.568-89.578), mean pressure <70 mmHg (P = 0.008; OR, 11.470; 95% CI, 1.920-68.546) and diabetes (P = 0.009; OR, 9.621; 95% CI, 1.779-52.032) as significant independent risk factors for SCI. CONCLUSIONS There were multiple factors predicting the risk of SCI after the FET technique. Paraplegia may be prevented by avoiding deep insertion of the stent graft and by keeping blood pressure elevated after the operation.

Cold blood spinoplegia under motor-evoked potential monitoring during thoracic aortic surgery

OBJECTIVE Motor-evoked potential monitoring is used to prevent paraplegia during thoracic aortic surgery. Multidetector computed tomography has been used preoperatively to detect the Adamkiewicz artery, but the hemodynamic significance of the Adamkiewicz artery is controversial. This study aims to evaluate whether the multidetector computed tomography-defined Adamkiewicz artery is hemodynamically essential and needs to be reconstructed with cold blood spinoplegia under motor-evoked potential monitoring. METHODS From 2005 to 2008, both preoperative multidetector computed tomographic analysis and intraoperative neurogenic motor-evoked potential monitoring with cold blood infusion into the clamped segment of the aorta were done in 15 patients. A motor-evoked potential decrease to less than 50% of the initial value at 3 minutes after cold blood infusion determined the hemodynamic significance of the multidetector computed tomography-defined Adamkiewicz artery. Adamkiewicz arteries determined to be essential were reconstructed, and those determined to be nonessential were sacrificed. RESULTS The Adamkiewicz artery was involved in the clamped segment of the aorta in 11 cases. After cold blood infusion, 8 patients experienced no significant motor-evoked potential decrease, and Adamkiewicz artery ligation was undertaken, whereas a moderate motor-evoked potential decrease was noted in 1 patient, prompting reconstruction. None of these 9 patients had permanent neurologic deficits. In 2 patients, the Adamkiewicz artery was reconstructed based on motor-evoked potential findings, with paraparesis occurring in 1 patient. In 4 patients without Adamkiewicz artery involvement in the clamped segment, there was no neurologic deficit. CONCLUSIONS Cold blood infusion accelerates motor-evoked potential changes and might enable decision making regarding the need for reconstruction of multidetector computed tomography-defined Adamkiewicz arteries. Cold blood-loaded motor-evoked potential is beneficial to minimize Adamkiewicz artery reconstruction time and limit spinal cord ischemia.

Late Occurrence of Atrial Arrhythmias After the Simple Left Atrial Procedure for Chronic Atrial Fibrillation in Mitral Valve Surgery

BACKGROUND We postulated that chronic atrial fibrillation (AF) associated with mitral valve disease originated from the distended left atrium and is maintained by itself. We had performed a simple left atrial procedure for the elimination of chronic AF associated with mitral valve disease in patients from 1993 to 1998. This paper evaluated the long-term results of the simple left atrial procedure after more than 10 years, and discussed the late occurrence of atrial arrhythmias in relation to the left atrial procedure. METHODS Fifty-two patients were examined after the simple left atrial procedure concomitant with mitral valve surgery retrospectively. We divided the patients into two groups with or without the elimination of AF (AF group and non-AF group). The disappearance of AF was estimated by electrocardiography, and atrial function was estimated by transthoracic echocardiography. The elimination of chronic AF and the recovery of atrial systolic function after surgery were evaluated during more than 10 years of follow-up. RESULTS In a total of 702.5 patient-years of follow-up (range, 11.3 to 16.1 years; mean, 13.5 ± 3.5 years), AF disappeared in 73% of the patients (38 of 52) at 5 years and in 69% of the patients (36 of 52) at 10 years after the simple left atrial procedure. Among the preoperative and intraoperative variables, a long duration of AF was the only predictive factor for late recurrences of AF (p < 0.05). In the sinus rhythm group, 2 of 36 patients remained in left atrial tachycardia. The final success rate in elimination of AF and atrial tachycardia was 34 of 52 patients (65.3%) at 10 years. An atrial kick was detected in 60% of patients across the mitral valve and in 100% of patients across the tricuspid valve by transthoracic echocardiography. CONCLUSIONS The simple left atrial procedure could terminate chronic AF associated with mitral valve disease and maintain sinus rhythm for more than 10 years in 65% of chronic AF patients. Left atrial tachycardia was a troublesome complication after cryoablation toward mitral valvular annulus. This study shows the long-term results and problems of the simple left atrial procedure for more than 10 years of follow-up.

Ascending Aorta Dissection Associated With Bicuspid Aortic Valve : Considerations 4 Years After Combined Coronary Artery Bypass Grafting and Mitral Valve Replacement

Aortic dissection etiology involve many factors that are difficult to identify clearly. We report a 47-year-old man who underwent a Bentall operation with reattachment of bypass grafts for a dissecting aneurysm (DeBakey type II) 4 years after combined triple coronary artery bypass grafting and mitral valve replacement. This case appeared to be associated with factors leading to dissecting aneurysm although it remains unclear which was more influential congenital bicuspid aortic valve or proximal anastomosis of venous grafts or both. This case suggests the need to consider appropriate timing in surgical intervention for cases of congenital bicuspid aortic valves and the selection of additional aortic valve replacement in initial surgery.

Efficacy of Cardiopulmonary Rehabilitation With Adaptive Servo-Ventilation in Patients Undergoing Off-Pump Coronary Artery Bypass Grafting

BACKGROUND Postoperative complications after cardiac surgery increase mortality. This study aimed to evaluate the efficacy of cardiopulmonary rehabilitation with adaptive servo-ventilation (ASV) in patients undergoing off-pump coronary artery bypass grafting (OPCAB). METHODS AND RESULTS A total of 66 patients undergoing OPCAB were enrolled and divided into 2 groups according to the use of ASV (ASV group, 30 patients; non-ASV group, 36 patients). During the perioperative period, all patients undertook cardiopulmonary rehabilitation. ASV was used from postoperative day (POD) 1 to POD5. Hemodynamics showed a different pattern in the 2 groups. Blood pressure (BP) on POD6 in the ASV group was significantly lower than that in the non-ASV group (systolic BP, 112.9±12.6 vs. 126.2±15.8 mmHg, P=0.0006; diastolic BP, 62.3±9.1 vs. 67.6±9.3 mmHg, P=0.0277). The incidence of postoperative atrial fibrillation (POAF) was lower in the ASV group than in the non-ASV group (10% vs. 33%, P=0.0377). The duration of oxygen inhalation in the ASV group was significantly shorter than that in the non-ASV group (5.1±2.2 vs. 7.6±6.0 days, P=0.0238). The duration of postoperative hospitalization was significantly shorter in the ASV group than in the non-ASV group (23.5±6.6 vs. 29.0±13.1 days, P=0.0392). CONCLUSIONS Cardiopulmonary rehabilitation with ASV after OPCAB reduces both POAF occurrence and the duration of hospitalization.

Treatment Strategy for Acute Type A Aortic Dissection Complicated with Organ Ischemia

OBJECTIVE We report our current treatment strategy for acute type A aortic dissection with organ ischemia as well as notable findings in our experience. MATERIALS AND METHODS Among 101 cases of acute type A aortic dissection, 25 had organ ischemia. Malperfusion was assessed at the aorta, proximal portion of the branch, organ parenchyma, and organ function by means of multiple modalities, including transesophageal echocardiography (TEE), near-infrared spectroscopy, and physical examinations. It was assessed every time the perfusion status was altered. RESULTS There were three operative deaths and one late hospital death. Uncertainty of symptoms and inadequate preoperative assessment in an emergent situation indicated the necessity of an overall check-up of organ ischemia in the operating room on a routine basis. Multi-modality assessment including TEE was helpful for this purpose. Two cases indicated that recovery of a true lumen could be inadequate despite true lumen perfusion including central cannulation. Thrombus in the false lumen appeared to be responsible. CONCLUSIONS To solve practical problems in treating acute type A dissection with organ ischemia, real-time information on organ perfusion is important for detecting the presence of malperfusion, making an appropriate strategy, and immediately assuring the efficacy of the means taken.

Mid-term results of the box pulmonary vein isolation and the cryo-maze procedure for chronic atrial fibrillation associated with mitral valve disease

PurposeWe performed box pulmonary vein isolation and the modified Maze procedure using cryoablation (cryo-maze) to eliminate chronic atrial fibrillation (AF) associated with mitral valve disease from 1999 to 2004. This article compares the elimination rate of chronic AF and the postoperative occurrence of new atrial tachycardia after both procedures over a follow-up period of >5 years.MethodsA total of 75 patients were enrolled in the study. Among them, 40 patients underwent box pulmonary vein isolation for chronic AF concomitant with solitary mitral valve surgery. Another 35 patients underwent the cryo-maze procedure for chronic AF concomitantly with both mitral and tricuspid valve surgeries. We evaluated the postoperative AF elimination rate and the occurrence of atrial tachycardia.ResultsDuring a total of 622.5 patient-years of followup, AF disappeared in 26 of 40 (65%) patients after the box pulmonary vein isolation and in 26 of 35 (74%) patients after the cryo-maze procedure at 5 years. Common atrial flutter occurred in 2 of 40 (5.0%) patients after the pulmonary vein isolation procedure. Left atrial Received: 8 December 2010 / Accepted: 20 April 2011

Three-dimensional CT Venography: A Diagnostic Modality for the Preoperative Assessment of Patients with Varicose Veins

OBJECTIVE We preoperatively assessed varicose veins by means of computed tomography (CT) with contrast injection in the veins of the lower extremity (CT venography). This paper reports the procedures, results and implications of CT venography from the surgical aspect. METHODS A total of 48 legs in 39 patients were examined. Contrast medium was diluted ten-fold and injected into the lower extremity veins, often using a dual route of injection. The images were reconstructed with the volume-rendering method. RESULTS CT venography clearly visualized the veins with a small amount of contrast medium and facilitated the identification of anatomy that was not suitable for passing the stripper. In addition, CT venography helped identify unusual types of varicose veins or uncommon sites of inflow of small saphenous veins. Such information was helpful for avoiding unexpected vascular injury or for minimizing skin incision. Dual-route injection was beneficial to minimize the blind zones. Doppler ultrasound could be more focused on hemodynamic assessment and determination of incision sites. CONCLUSIONS CT Venography is feasible in all cases of varicose veins. When performed in conjunction with ultrasonography, it appears to facilitate the safe and efficient treatment of various types of varicose veins.

Prospects for clinical applications of polymer-coated haemoconcentrator on extracorporeal circuit in cardiopulmonary bypass surgeries.

Purpose Extracorporeal circulation circuits used in cardiopulmonary bypass surgeries are increasingly being coated with polymer materials to reduce the thrombogenicity of extracorporeal devices. However, a haemoconcentrator, which corrects haematocrit and electrolyte imbalances, is not coated with polymers. In this study, we sought to assess the filtration performance of polymer-coated haemoconcentrators in order to obtain insight into their prospects for use in clinical applications. Methods In vitro experiments were performed to evaluate the water pressure and flow properties of polymer-coated haemoconcentrators by comparing 3 polymer-coated haemoconcentrators with 3 non-coated haemoconcentrators. The cross-sectional surfaces of both types of haemoconcentrators were observed using a scanning electron microscope (SEM). Results The slopes of the regression lines for estimating the filtrated fluid flow as a function of the transmembrane pressure were 6.286 ± 0.320 for polymer-coated haemoconcentrators and 3.712 ± 0.170 for non-coated haemoconcentrators. These slopes were found to be significantly different and indicate that the filtration velocity is enhanced in polymer-coated haemoconcentrators over that in non-coated haemoconcentrators. However, the hollow fibre damage observed by SEM was not shown to contribute to higher filtration flow in the polymer-coated haemoconcentrator. Taking these results into consideration, we hypothesise that a polymer coating makes a foreign surface on a hollow fibre slippery, owing to the hydrophobicity of the polymer, thereby enhancing the velocity of the filtration. Conclusions The results of this preliminary investigation suggest that a polymer coating can enhance the filtration performance of a haemoconcentrator and that polymer-coated haemoconcentrators might be useful in clinical applications.

Treatment strategy for infections in patients with permanent pacemakers

Infection after pacemaker implantation can be the most lethal potential complication, although such infections occur infrequently. In this report, we review our experience with patients who were infected after pacemaker implantation and assess their treatment. The infection rate was 1.3% (9 patients) after 712 operations performed in 588 patients. Four men and five women were infected; their mean age was 74.4 years (range, 66 to 86 years). The infection rates after the initial implantation and the second operation were 0.85% and 2.7%, respectively. Two of the nine patients underwent palliative two-stage operations, which included first removing the generator and subsequent irrigation with temporary pacing before a new pacemaker system was implanted during the second stage. Two patients underwent radical two-stage operations (without abandoning old leads); one of these underwent cardiopulmonary bypass after treatment for generalized septicemia. One patient underwent relocation of the pocket 1 month after the onset of pacemaker infection. The remaining four patients underwent palliative one-stage operations, in which new pacemaker units were implanted in the contralateral sides at the same time the first generator was removed. All of the patients were alive and well postoperatively. No recurrent infections were recognized. Therefore, a palliative one-stage operation (“retain old leads” procedure) might be an effective procedure of choice for patients with localized infections over the pocket. Furthermore, irrigation with function water and systemic antibiotic prophylaxis could be effective as measures against infection.