Atsuhiro Nakashima

Effects of hypothermia during cardiopulmonary bypass and circulatory arrest on sympathetic nerve activity in rabbits

OBJECTIVES Little is known about the effect of hypothermia on neural regulation. We investigated the effects of hypothermia during cardiopulmonary bypass (CPB) on control of renal (RSNA) and lumbar sympathetic nerve activity (LSNA), and plasma catecholamine levels. METHODS We directly measured RSNA (n = 14) and LSNA (n = 6) during CPB in anesthetized rabbits. CPB was performed via cannulae in the aortic root for arterial perfusion and the right atrium for venous drainage. Systemic hypothermia was induced by core cooling. RSNA and LSNA were recorded at the nasopharyngeal temperature of 37, 30, 24, and 18 degrees C and after rewarming up to 37 degrees C while keeping mean arterial pressure at 70 mmHg by altering perfusion flow. Other variables such as blood gases or electrolytes were kept constant. RESULTS RSNA at the temperature of 30, 24, and 18 degrees C significantly decreased by 91, 97, and 95% from control (37 degrees C), respectively. LSNA decreased by 18, 57, and 89% from control as well. The decreases in RSNA at 30 and 24 degrees C were greater than those in LSNA (P < 0.05). At 18 degrees C both RSNA and LSNA nearly disappeared. Circulatory arrest for 20 min during hypothermia at 18 degrees C caused no increase in RSNA while it increased LSNA. Plasma catecholamine levels at 18 degrees C were not different from those at 37 degrees C. Rewarming to 37 degrees C increased RSNA and LSNA by 321 and 92% from control (37 degrees C before cooling), respectively (P < 0.01). CONCLUSIONS Hypothermia progressively decreased and rewarming markedly increased sympathetic nerve activity, but the effects of hypothermia on RSNA and LSNA were not uniform.

Left ventricular performance in aortic valve replacement

We analyzed the mid-term left ventricular (LV) performance after aortic valve replacement (AVR). We measured LV contractility (end-systolic elastance: Ees), afterload (effective arterial elastance: Ea) and efficiency (ventriculoarterial coupling: Ea/Ees; ratio of stroke work and pressure-volume area: SW/PVA) based on transthoracic echocardiography data obtained before, after and approximately 1 year after isolated AVR in 263 patients with aortic stenosis (AS group; n=116), aortic regurgitation (AR group; n=93) or aortic stenosis and regurgitation (ASR group; n=54). The LV volume was calculated by the Teichholz M-mode method. Ees and Ea were approximated as follows: Ees=mean blood pressure/minimal LV volume; Ea=systolic blood pressure/(maximal LV volume-minimal LV volume). Thereafter, Ea/Ees and SW/PVA were calculated. Arterial blood pressure was measured using manchette methods. Ees and Ea decreased after AVR in the AS group, but increased in the AR group. Ea/Ees and SW/PVA worsened after AVR in the AR group, but improved during a 1-year period after AVR in all groups. Contrasting effects of AVR on LV contractility and afterload between AS and AR were clearly demonstrated. The mid-term LV contractility and efficiency after AVR were excellent and satisfactory. However, LV efficiency worsened early after AVR in AR patients.

Thoracoscopic ultrasonic coagulation of thoracic duct in management of postoperative chylothorax

Chylothorax is a rare but potentially serious complication of cardiac operations. We report here a 72-year-old man who underwent replacement of a descending aneurysm with a synthetic graft for dissecting aneurysm (IIIa). A persistent postoperative chylothorax developed, which necessitated continuous drainage, despite conservative treatment more than 12 days. Thoracoscopic high-frequency ultrasonic coagulation of the thoracic duct without clipping finally stopped chyle production. This method may be useful from the standpoint of minimal access, rapid recovery, less pain, and a shorter operation.

The efficacy of fluconazole in treating prosthetic valve endocarditis caused by Candida glabrata : report of a case

A case of active prosthetic valve infective endocarditis (PVE) due toCandida glabrata was successfully treated by the systemic administration of fluconazole. A 66-year-old Japanese man with infective endocarditis of unknown etiology underwent aortic and mitral valve replacement to treat severe aortic and mitral regurgitation associated with multiple organ failure. Postsurgical cultures of arterial blood were repeatedly positive forC. glabrata, and therefore fluconazole was administered either intravenously or orally at a dose of 400 mg/day for 46 days. During that time the signs of inflammation including fever such as an elevated white blood cell count and the presence of C-reactive protein (CRP) all improved while the blood cultures became negative. Fluconazole is thus considered to be effective in treating PVE caused byC. glabrata. When administering this treatment, it is also important to monitor the patients renal and liver function.

The novel EuroSCORE II algorithm predicts the hospital mortality of thoracic aortic surgery in 461 consecutive Japanese patients better than both the original additive and logistic EuroSCORE algorithms

OBJECTIVES The European System for Cardiac Operative Risk Evaluation (EuroSCORE) II was developed to improve the overestimation of surgical risk associated with the original (additive and logistic) EuroSCOREs. The purpose of this study was to evaluate the significance of the EuroSCORE II by comparing its performance with that of the original EuroSCOREs in Japanese patients undergoing surgery on the thoracic aorta. METHODS We have calculated the predicted mortalities according to the additive EuroSCORE, logistic EuroSCORE and EuroSCORE II algorithms in 461 patients who underwent surgery on the thoracic aorta during a period of 20 years (1993-2013). RESULTS The actual in-hospital mortality rates in the low- (additive EuroSCORE of 3-6), moderate- (7-11) and high-risk (≥11) groups (followed by overall mortality) were 1.3, 6.2 and 14.4% (7.2% overall), respectively. Among the three different risk groups, the expected mortality rates were 5.5 ± 0.6, 9.1 ± 0.7 and 13.5 ± 0.2% (9.5 ± 0.1% overall) by the additive EuroSCORE algorithm, 5.3 ± 0.1, 16 ± 0.4 and 42.4 ± 1.3% (19.9 ± 0.7% overall) by the logistic EuroSCORE algorithm and 1.6 ± 0.1, 5.2 ± 0.2 and 18.5 ± 1.3% (7.4 ± 0.4% overall) by the EuroSCORE II algorithm, indicating poor prediction (P < 0.0001) of the mortality in the high-risk group, especially by the logistic EuroSCORE. The areas under the receiver operating characteristic curves of the additive EuroSCORE, logistic EuroSCORE and EuroSCORE II algorithms were 0.6937, 0.7169 and 0.7697, respectively. Thus, the mortality expected by the EuroSCORE II more closely matched the actual mortality in all three risk groups. In contrast, the mortality expected by the logistic EuroSCORE overestimated the risks in the moderate- (P = 0.0002) and high-risk (P < 0.0001) patient groups. CONCLUSIONS Although all of the original EuroSCOREs and EuroSCORE II appreciably predicted the surgical mortality for thoracic aortic surgery in Japanese patients, the EuroSCORE II best predicted the mortalities in all risk groups.

Follicular carcinoma of the thyroid with massive invasion into the cervical and mediastinum great veins: Our own experience and literature review

Thyroid carcinomas with massive intralumen invasion of the great veins are extremely rare and reported to have poor prognosis. We report a case of a poorly differentiated follicular carcinoma of the thyroid with extensive invasion into the bilateral internal jugular veins, brachiocephalic vein, and superior vena cava. All of the seven major drainage veins from the thyroid were involved by tumor thrombus. The patient was successfully treated by surgical resection including removal of the tumor thrombus and repair of the great veins. The importance of preoperative radiological findings, treatment, and outcome are discussed along with a literature review.

Mechanical Prosthesis Is Reasonable for Mitral Valve Replacement in Patients Approximately 65 Years of Age

BACKGROUND The long-term results of mitral valve replacement (MVR; n = 631) with a bileaflet mechanical prosthesis or a Carpentier-Edwards Perimount bioprosthesis were evaluated in Japanese patients of different age groups. METHODS A total of 507 bileaflet mechanical prostheses and 124 bioprostheses have been implanted since 1982 at our institution. Follow-up was completed for 6,598 patient-years in 98.4% of the cases. RESULTS Among the patients 70 years of age and older, the rate of freedom from valve-related death and valve-related morbidity at 10 years after surgery were significantly better in the bioprostheses group (93.3% ± 6.4% and 83.7% ± 8.7%, respectively; n = 35) than in the mechanical prostheses group (71.1% ± 8.0% and 60.9% ± 8.9%, respectively; n = 82), and neither structural valve deterioration (SVD) nor resulting re-MVR were observed for bioprostheses. In contrast, among the patients 64 years and younger, no significant differences were observed in long-term survival between the mechanical prostheses group (n = 347) and the bioprostheses group (n = 76), while significantly lower rates of freedom from SVD and re-MVR were observed in the bioprostheses group compared with those obtained in the mechanical prostheses group. As for the controversial intermediate-age group of 65 to 69 years, the general tendencies were similar to those observed in the group 64 years and younger. CONCLUSIONS Based on our comparative evaluation, bioprostheses should be chosen for MVR in patients 70 years of age and older, whereas mechanical prostheses were better in the patients 64 years of age and younger. The use of bioprostheses in Japanese patients 65 to 69 years of age is not preferable for preventing SVD and subsequent re-MVR.

Atypical presentation of an apical pseudoaneurysm in a patient on prolonged left ventricular mechanical support.

Prolonged support with left ventricular assist system (LVAS) increases the risk of device-related infection. We experienced a rare complication of LVAS: an infectious aneurysm at the apical cannula, which appeared with atypical presentation. A 27-year-old male, who developed acute aggravation of dilated cardiomyopathy, was placed on extra-corporeal type LVAS. Six months later, the patient suffered from methicillin-resistant Staphylococcus aureus (MRSA) sepsis that lasted for as long as three months despite intensive antibiotic therapy. At 17 months after the implantation, he presented with obstructive ileus. Monthly assessment with transthoracic echocardiography (TTE) did not document any abnormalities around the ventricle. A contrast computed tomographic (CT) scan revealed a huge apical aneurysm protruding into the preperitoneal space. The aneurysm oppressed the transverse colon, resulting in obstructive ileus. Aneurysmectomy was carried out and MRSA was identified from the resected tissue. We reached the precise diagnosis with a CT-scan, although routine assessment with TTE failed to reveal abnormalities. Knowledge of this complication is essential in LVAS management. This is certainly rare, but possibly occurs in all the patients on prolonged LVAS support. Early and accurate diagnosis together with aggressive intervention would bring favorable outcome in such serious cases.

Risk factors for posttransfusion graft versus host disease, mediastinitis, and late cardiac tamponade in heart surgery. Survey of 119 Japanese institutions.

OBJECTIVE Correlations and risk factors remain to be unclarified for post-heart-surgery posttransfusion graft-versus-host disease, mediastinitis, and late cardiac tamponade caused by deteriorated host-defense mechanisms due to cardiopulmonary bypass both with and without steroid usage. METHODS We sent questionnaires to 298 Japanese cardiovascular institutions asking for institution profiles, including infection control, steroid use in cardiopulmonary bypass, and prevalence of mediastinitis, late cardiac tamponade, and posttransfusion graft-versus-host disease during 1994. The overall prevalence of posttransfusion graft-versus-host disease since the start of service (from establishment of institution to date) was also requested. RESULTS The number of pump cases at the 119 institutions responding (40%) were 91.6 +/- 67.9 cases/institution (total = 10,904). The prevalence of mediastinitis was 1.2 +/- 1.8 and that of late cardiac tamponade 1.0 +/- 1.8%. Posttransfusion graft-versus-host disease occurred in 1 of 10,904 patients (0.01%) during 1994 at an institution where steroids and nonirradiated blood were used in surgery. The simple institutional mean prevalence of posttransfusion graft-versus-host disease since establishing institutions was 0.08 +/- 0.13%. Of the 119 institutions surveyed, 86 used steroids in all pump cases (72%); 11 institutions used steroids in a limited number of cases (9%). The institutional mean of methylprednisolone-converted steroid dose was 21.5 +/- 16.4 mg/kg (n = 119). In multivariate regression analysis, operation time (p = 0.005) for mediastinitis, steroid usage (all, limited, or no cases) (p = 0.01) and % aneurysm (p = 0.05) for late cardiac tamponade, and steroid dosage (p = 0.002) for posttransfusion graft-versus-host disease were identified as significant risk factors. CONCLUSION Our results suggest that massive steroid administration for cardiopulmonary bypass may increase the risk of posttransfusion graft-versus-host disease and late cardiac tamponade, but not mediastinitis.

Drug infusion through a branch of the aortocoronary vein graft for refractory coronary spasm

We describe two cases of coronary artery spasm that occurred during open heart operations and were treated by coronary artery bypass grafting. Vasodilators and calcium antagonists were infused directly into the right coronary artery via the side branch of the saphenous vein graft. Both patients were weaned successfully from cardiopulmonary bypass.