Kazuyoshi Tajima

Cardiopulmonary bypass and cellular immunity: Changes in lymphocyte subsets and natural killer cell activity

To investigate whether cell-mediated immunity responses are suppressed or activated by the effect of cardiopulmonary bypass (CPB), we studied peripheral blood lymphocyte subsets and antibody-dependent cell-mediated cytotoxicity in 52 adult patients who had undergone open heart operations. Lymphocyte function also was studied with regard to mixed lymphocyte reaction, which indicates the amount of DNA synthesis of lymphocytes, and natural killer (NK) cytotoxicity, which represents the killing activity of NK cells on the tumor cells (K-562), in 11 patients. The total T lymphocyte (OKT3+ and OKT11+) number showed no significant change during CPB. Suppressor/cytotoxic T cell (OKT8+) and NK cell (Leu7+ and Leu11+) numbers were found to be remarkably increased. However, helper/inducer T cell (OKT4+) and B cell (Leu12+) numbers were decreased during CPB. Antibody-dependent cell-mediated cytotoxicity was elevated during CPB. All of these changes were almost returned to the preoperative levels by the seventh day after operation. Mixed lymphocyte reaction and NK cytotoxicity were also activated during CPB. The results show that heart operations in which cardiopulmonary bypass is used are associated with activation of cytotoxic cell-mediated immunity.

Early and Late Outcomes of Aortic Valve Replacement in Dialysis Patients

BACKGROUND Few data are available on the outcomes of aortic valve replacement (AVR) in dialysis patients. Valve selection has been controversial, and systemic calcification in these patients has been an important concern. This study reports our experiences and evaluates whether dialysis patients can be treated in a way that is similar to nondialysis patients. METHODS A retrospective review was performed on 73 AVRs (43 men, 29 women), including one redo operation, for dialysis patients between 1995 and 2007. Mean age was 65.0 +/- 8.3 years. The bioprosthesis was basically selected for elderly patients as for nondialysis patients. RESULTS For a severely calcified ascending aorta, the femoral or subclavian artery was selected for arterial cannulation in 9 patients (12.3%), and aortic cross-clamping under temporary circulatory arrest with moderate hypothermia was applied in 17 (23.3%). Implanted were 51 mechanical and 22 bioprosthetic valves. Four elderly patients in poor general condition received high-performance mechanical valves instead of bioprosthesis to avoid aortic root enlargement. There was no stroke during the perioperative period. Hospital mortality was 6.8%. The overall actuarial survival rate was 74.6% +/- 5.6%, 55.7% +/- 7.6%, and 39.9% +/- 9.7% at 3, 5, and 10 years, respectively. CONCLUSIONS The results for the dialysis patients after AVR were satisfactory. Dialysis patients can be treated in AVR just like nondialysis patients. Valve selection and surgical strategy on a case-by-case basis are important to improve the clinical outcomes in dialysis patients.

Safer aortic crossclamping during short-term moderate hypothermic circulatory arrest for cardiac surgery in patients with a bad ascending aorta

OBJECTIVE Cardiac surgery in patients with severely atherosclerotic or porcelain ascending aorta is technically challenging, with markedly increased risk of atheroembolism. We describe a technique of meticulous crossclamping of a difficult aorta during short-term moderate hypothermic circulatory arrest. METHODS From 1997 to 2007, we found 40 patients (mean age, 70 +/- 8 years), including 14 patients undergoing hemodialysis, whose preoperative computed tomographic and intraoperative epiaortic ultrasonographic scans revealed eggshell calcification (n = 15) or protruding atheromas (n = 25) of the ascending aorta. They underwent cardiac surgery (aortic, 31 patients; mitral, 3 patients; both, 5 patients; and coronary alone, 1 patient) by means of meticulous crossclamping during hypothermic circulatory arrest for 3.4 +/- 1.5 minutes at a rectal temperature of 29.0 degrees C +/- 2.3 degrees C. During hypothermic circulatory arrest, we performed only internal inspection to identify the safe location of crossclamping in 21 patients, whereas we required debridement of calcification or atheroma by using the Cavitron Ultrasonic Surgical Aspirator (Tyco Healthcare, Mansfield, Mass) for safe crossclamping in 19 patients. RESULTS By using this technique, no patients died during the hospital stay. Stroke occurred in 1 (2.5%) patient, and transient agitation occurred in 1 patient. Re-exploration for bleeding was required in 1 patient, and wound infection occurred in 2 patients. During follow-up, with a median time of 5.2 years, the overall survival rates were 100%, 90%, and 76% at 1, 3, and 5 years, respectively. Three patients required reoperations during the follow-up period because of pseudoaneurysm in 2 patients and prosthetic valve infection in 1 patient. CONCLUSION Short-term moderate hypothermic circulatory arrest is quite useful for safe aortic crossclamping after internal inspection or debridement in high-risk patients with a severely atherosclerotic aorta.

Simplified Management of Hemodialysis-Dependent Patients Undergoing Cardiac Surgery

BACKGROUND The mortality and morbidity rates are high after cardiac surgery in hemodialysis (HD)-dependent patients. To improve their outcomes, optimal perioperative managements should be discussed. METHODS A retrospective analysis of 245 HD patients who underwent cardiac surgery between 1994 and 2007 was conducted. The basic management strategies were (1) low-potassium HD for 2 days before surgery, (2) only hemofiltration during cardiopulmonary bypass, and (3) start of regular intermittent HD on the first postoperative day. Continuous venovenous hemodiafiltration was applied only for patients with hemodynamic instability. RESULTS The causes of renal failure included diabetic (n = 89, 36%), glomerulonephritis (n = 49, 20%), and unknown (n = 75, 31%). The history of HD was 9.7 +/- 7.6 years. The operative procedures included coronary (n = 135), valve (n = 103), and others. The amount of intraoperative ultrafiltration was 6,123 +/- 324 mL during cardiopulmonary bypass for 197 +/- 67 minutes. Two hundred eight patients (85%) were managed with only intermittent HD, whereas 36 patients (15%) needed continuous venovenous hemodiafiltration. The use of continuous venovenous hemodiafiltration significantly declined during the year (26% before 2003 and 3% after 2003; p < 0.001). The amount of fluid removal on the first postoperative day was 1,297 +/- 81 mL. The hospital mortality was 9.7% with the causes including infection (n = 11), cardiac events (n = 6), gastrointestinal events (n = 5), and stroke (n = 2). A multivariate logistic regression analysis revealed that selection of intermittent HD or continuous venovenous hemodiafiltration was not related to the hospital mortality. CONCLUSIONS Simplified management only with intermittent HD can be safely performed in most HD-dependent patients undergoing cardiac surgery.

Predictors for early and late outcomes after coronary artery bypass grafting in hemodialysis patients.

BACKGROUND Markedly higher hospital and long-term mortality after coronary artery bypass grafting (CABG) have been reported in hemodialysis (HD)-dependent patients. We tried to identify the predictors for short-term and long-term outcomes after CABG, which have not been well studied. METHODS Between 1993 and 2010, 152 patients undergoing HD (117 men; HD duration of 8.7±8.0 years) underwent isolated CABG. Our strategies included use of a single internal thoracic artery (ITA) in patients with diabetes mellitus (DM), bilateral ITAs in patients without DM, and possible avoidance of cardiopulmonary bypass (CPB) after 2003. RESULTS Thirty-six percent of patients underwent conventional CABG: 20% had on-pump beating heart procedures and 44% had off-pump procedures, with 2.8±1.0 anastomoses. Hospital mortality was 10.6% with improvement to 6.8% after 2003. Predictors for hospital death were left ventricular ejection fraction (LVEF) less than 0.40 (p=0.042), use of CPB (p=0.046), and postoperative need for continuous hemofiltration (p=0.037). After follow-up of 49±42 months, the overall survival rates were 76.9%, 60.0%, 43.9%, and 36.2% and the cardiac events-free rates were 77.0%, 70.1%, 55.9%, and 44.8% at 3, 5, 8, and 10 years, respectively, in the Kaplan-Meier model. A multivariate Cox proportional hazard model identified age older than 63 years (p=0.014), DM (p=0.036), and peripheral artery disease (PAD) (p=0.044) as predictors for late death, and DM (p=0.038) and LVEF less than 0.40 (p=0.027) as predictors for late cardiac events. CONCLUSIONS Although early outcomes have been improved by off-pump techniques, late outcomes are not satisfactory in patients who rely on HD and undergo CABG. To improve late outcomes we may need aggressive management of DM, PAD, and low LVEF in those patients.

Can we predict the site of entry tear by computed tomography in patients with acute type a aortic dissection

In patients with acute type A aortic dissection (AAD), localization of the primary entry tear to be excluded is of major importance for intervention.

Valve Selection for the Aortic Position in Dialysis Patients

BACKGROUND Prosthetic valve selection in dialysis patients remains controversial because of the limited data available. This study aimed to clarify late clinical outcomes and discuss strategies for optimal valve selection in dialysis patients. METHODS We retrospectively analyzed the data obtained from 406 consecutive patients who underwent aortic valve replacement between 1995 and 2010. We compared valve-related outcomes among 89 dialysis and 317 nondialysis patients. We selected bioprostheses for all patients older than 65 to 70 years, irrespective of the renal function. RESULTS Dialysis was found to be a significant risk factor for bleeding events (hazard ratio, 3.98; 95% confidence interval, 2.51 to 6.30; p < 0.001), however, no significant differences were observed according to the type of prosthesis. The overall survival was significantly worse in the dialysis patients (63% versus 85% at 5 years; p < 0.001), and freedom from structural valve deterioration was also lower in the dialysis patients (82% versus 100% at 5 years; p < 0.001). Among the dialysis patients, an advanced age (≥ 70 years; hazard ratio, 3.53; p = 0.011), diabetes mellitus (hazard ratio, 2.48; p = 0.041), and concomitant coronary artery bypass grafting (hazard ratio, 1.99; p = 0.071) were independent predictors for late death based on a multivariate analysis. CONCLUSIONS Our valve selection criteria in dialysis patients, which are the same as the current practice guidelines for nondialysis patients, are acceptable. Bioprostheses can be considered in all dialysis patients with diabetes or coronary artery disease.

Effects of the side of arteriovenous fistula on outcomes after coronary artery bypass surgery in hemodialysis-dependent patients.

OBJECTIVE The aim of the study was to determine whether using the in situ internal thoracic artery (ITA) graft ipsilateral to the arteriovenous fistula adversely affects the outcomes after isolated coronary artery bypass grafting (CABG) in the dialysis-dependent patients to answer the concerns of a possible steal and consequent myocardial ischemia. METHODS We categorized 155 dialysis patients undergoing isolated CABG between January 1993 and December 2011 into 108 patients (70%, ipsilateral group) whose left anterior descending artery (LAD) was revascularized with the ITA ipsilateral to the arteriovenous fistula and 47 patients (contralateral group) whose LAD was grafted with the ITA opposite to the fistula, to compare their early and late outcomes. RESULTS While 94% of the ipsilateral group had left fistula, 55% of the contralateral group had left fistulas. The LAD was grafted with the left ITA in 94% of the ipsilateral group, whereas it was grafted with left (49%) or right (51%) ITAs in the contralateral group. There was no significant difference in hospital mortality between the groups (ipsilateral 10.2% vs contralateral 10.6%). After follow-up for 55 ± 42 months, the overall survival (ipsilateral 58% vs contralateral 65% at 5 years) and cardiac event-free rates (ipsilateral 74% vs contralateral 68% at 5 years) were also similar between the groups by log-rank tests (P = .90 and P = .07). CONCLUSIONS Revascularization of the LAD using the in situ ITA graft ipsilateral to the arteriovenous fistula increases neither the operative mortality nor the risks of late death and cardiac events after isolated CABG in dialysis patients.

Results of Isolated Valve Replacement in Hemodialysis Patients

Frequent bleeding complications and poor long-term results have been reported after valve replacement in hemodialysis patients. We use mainly bileaflet mechanical valves with low-dose warfarin therapy (target international normalized ratio, 1.8–2.0) in such cases. Data of 27 hemodialysis patients undergoing isolated valve replacement from 1993 to 2002 were retrospectively analyzed. Bileaflet mechanical valves were selected in 23 patients and bioprostheses in 4. Those with mechanical valves were treated with mild anticoagulation therapy. There were 3 (11.1%) early deaths due to ischemic colitis, interstitial pneumonia, and ventricular arrhythmia. There were 3 late deaths and 5 bleeding complications during follow-up. The overall survival rate was 85.2% at 3 years and 72.9% at 5 years. The survival rate of patients with mechanical valves was 82.6% at 3 years and 76.7% at 5 years. One patient with a bioprosthesis experienced structural valvular deterioration after 3 years. The results demonstrate an acceptable long-term outcome. A bileaflet mechanical valve managed with mild anticoagulation therapy is a reasonable strategy for hemodialysis patients.

Long-term size follow-up of knitted Dacron grafts (Gelseal™) used in the ascending aorta

There is limited information about the size change of a knitted Dacron graft (Gelseal™) used in the thoracic aorta. We evaluated the diameters of the Gelseal™ grafts at a long-term follow-up for 3.7 ± 1.3 years (1-5.9 years; median, 4.0 years), which were used for replacement of the ascending aorta in 59 patients with acute aortic dissection. The early and late dilatation rates (LDRs) of the prosthetic grafts were calculated retrospectively based on the graft diameter at the level equivalent to the ascending aorta on the pre-discharge computed tomography (CT) scans and follow-up CT scans performed every year after surgery. Immediately after surgery (15 ± 7 days), the early dilatation of the Gelseal™ grafts was 26.0 ± 6.0% with significant correlations with the number of post-operative days (R = 0.500, P = 0.003). At the follow-up for 3.7 ± 1.3 years, the LDR was 10.5 ± 6.6%, which was also significantly correlated with the number of the post-operative years (R = 0.608, P = 0.001). Linear regression analysis indicated that the annual dilatation rate was ≈ 3.23%. During the follow-up, we have experienced no redo surgery due to graft fracture or false aneurysm formation at the anastomosis sites associated with the graft dilatation. In conclusion, the Gelseal™ graft used in the ascending aorta demonstrates a small but continuous increase in the diameter, up to 5 years after implantation, without any adverse events.