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Selective cerebral perfusion (SCP) and open distal anastomosis (OD) with hypothermia has been used as a popular means for circulatory assistance in aortic arch surgery. Although SCP has become accepted for brain protection, the influence of OD accompanying circulatory arrest on lower body ischemia is not known. We studied gastric tonometry (gastric intramucosal pH [pHi]) to estimate splanchnic ischemia during OD, and its relationship to postoperative organ function. In five patients (pts) (range, 65-78 years; mean, 71 years; group OD) who underwent arch replacement using SCP and OD with moderate hypothermia (25 degrees C) during the period from March to August of 1999, pHi was measured precardiopulmonary bypass (pre-CPB), 30 min of CPB (CPB30), 10 min after OD (OD10), at end of CPB, and post-CPB. Eight pts (range, 52-78 years; mean; 66 years) who underwent standard CPB (33 degrees C) during the same period (coronary artery bypass surgery in six and valve surgery in two) served as controls (group C). In group OD, pHi was significantly decreased at OD10 (7.35 +/- 0.03 at CPB30 vs. 7.23 +/- 0.07 at OD10, p < 0.05) but recovered by the end of CPB (7.32 +/- 0.02). Creatinine clearance on the first postoperative day (1POD) was significantly (p < 0.05) lower in group OD (82 +/- 40 ml/min) than in group C (126 +/- 25 ml/min), although there was no significant difference in preoperative values between the two groups. The pHi at OD10 did not correlate with the duration of OD (range, 30-47 min; mean, 38 min), whereas pHi at OD10 significantly correlated with BUN (r = -0.973, p = 0.0054), Cr(r = -0.977, p = 0.0043), and CCr (r = 0.908, p = 0.0328) on 1POD. One patient in group OD developed paraplegia and renal failure postoperatively. His pHi at OD10 was severely decreased to 7.11. These results suggest that intraoperative monitoring of pHi may be useful for the evaluation of visceral organ ischemia during OD in arch replacement and may contribute to improved technique for circulatory assistance in aortic surgery.

Endovascular stent grafts (ESGs) for the treatment of aortic aneurysm is becoming popular because it is less invasiveness for the patient. This new modality seems to be especially useful for treating high risk patients, such as those with end-organ dysfunction. In this study we retrospectively analyzed the results of ESG placement for patients with renal or hepatic dysfunction. From January 1996 to December 1997, six patients with end-organ dysfunction (two with descending thoracic aneurysm and four with abdominal aneurysm) underwent ESG placement. Five of these patients had renal dysfunction, with serum creatinine levels of 2.0 mg/dl or greater, and the remaining patient had hepatic dysfunction with a prothrombin time less than 60%. One of the patients also had severe atherosclerotic disease with a history of multiple brain infarctions. All the patients received custom made endovascular spiral Z stents covered with a woven Dacron (DuPont Co., Wilmington, DE) graft, which was delivered via a femoral artery under local anesthesia. None of the patients showed significant changes in renal or hepatic function after the procedure. None of the five patients with renal dysfunction needed hemodialysis after ESG placement, although the mean preoperative level of serum creatinine and blood urea nitrogen was 3.4 mg/dl and 42.0 mg/ dl, respectively. All the patients left the recovery room on postoperative day 1. These results indicated that endovascular stent graft placement is extremely useful in the treatment of aortic aneurysm patients with end-organ dysfunction.

Heparin coated bypass circuits have been reported to improve the biocompatibility of extracorporeal circulation, although it is still insufficient and improvable. Nitric oxide (NO) is known to inhibit platelet activation and inflammatory reactions. In this study, the authors evaluated exogenous NO infusion in enhancing the effect of a heparin coated bypass circuit on the biocompatibility of an extracorporeal circuit, especially in view of the attenuation of the inflammatory response. A miniature closed bypass circuit, including an oxygenator (BioActive surface; Carmeda, Stockholm, Sweden) was primed with fresh human heparinized blood and perfused with a centrifugal pump. Either pure N2 gas (control group: n = 7) or NO gas (NO group [100 ppm in N2]: n = 7) was infused to the oxygenator. NO metabolites (nitrite and nitrate), platelet count, thrombin-antithrombin III complex (TAT), alpha2-plasmin-plasminogen inhibitor complex (PIC), beta-thromboglobulin (beta-TG), platelet factor 4 (PF4), serotonin, complement 3 activation products (C3a), granulocyte elastase, and bradykinin were measured at 0, 30, 60, 120, and 180 min after starting perfusion. At every sampling point, platelet counts were significantly higher, and TAT, beta-TG, and bradykinin were lower in the NO group than in the control group. PF4, C3a, and granulocyte elastase were significantly lower in the NO group at 60, 120, and 180 min. These results suggest that NO gas infusion to the oxygenator enhances the biocompatibility of heparin coated extracorporeal circuits.

"Post perfusion syndrome" after cardiopulmonary bypass (CPB) has been known to be evoked by inflammatory reactions. To elucidate the effect of perfusate temperature during CPB on subsequent inflammatory reactions, serum levels of interleukin (IL)-6, IL-8, tumor necrosis factor-alpha, IL-1 beta, and polymorphonuclear (PMN) elastase were measured before and after (0, 12 hours, and 24 hours after) CPB in adult patients undergoing cardiac operations. Patients were divided into two groups: the normothermic CPB group (NOR, 34 degrees C perfusate temperature, n = 8) and hypothermic CPB group (HYP, 28 degrees C perfusate temperature, n = 8). In both groups, IL-6, IL-8, and PMN elastase levels were elevated during CPB, while the increase of tumor necrosis factor-alpha and IL-1 beta was not detected. The increase in IL-8 and PMN elastase levels at 12 hours after CPB was significantly less in NOR than in HYP (IL-8; NOR versus HYP, 15.1 +/- 12.9 versus 62.5 +/- 30.6 pg/ml, p < 0.05, PMN elastase; 394 +/- 200 versus 1085 +/- 523 micrograms/L, p < 0.05) while neither group showed any difference in IL-8 and PMN elastase at 24 hours after CPB. There was no difference in IL-6 between the two groups, and no significant increase in tumor necrosis factor-alpha and IL-1 beta levels were detected in either group after CPB. These results demonstrate that although CPB activated inflammatory reactions detected by IL-8 and PMN elastase activity, post operative persistence of these reactions were attenuated by warm CPB.

To achieve more physiologically successful cardiopulmonary bypass (CPB), the effects of a new synthetic protease inhibitor, nafamostat mesilate (FUT), were examined in open heart surgery. Thirty adult patients were divided into two groups. In Group F (GpF; n = 15), 2 mg/kg/hr of FUT was administered continuously during CPB and 0.2 mg/kg/hr before and after CPB. FUT was not given to Group C patients (GpC; n = 15), who acted as controls. Serotonin and histamine levels in plasma, platelet counts, platelet adhesive function levels, and alpha 2 plasmin inhibitor-plasmin complexes (PIC) were serially measured. The serotonin level in GpF was significantly lower at 5 min of CPB than in GpC. Histamine levels in GpC decreased remarkably after starting CPB, then later recovered; by contrast, they did not decrease in GpF during CPB. At 1 hr after CPB, platelet counts were higher (p < 0.01) in GpF (54 +/- 8%) than in GpC (41 +/- 10%), and platelet adhesion was lower (p < 0.01) in GpF (7 +/- 7%) than in GpC (34 +/- 13%). The PIC was significantly less in GpF than in GpC throughout the surgery. Blood loss in GpF was significantly reduced compared with that in GpC. In conclusion, FUT attenuated chemical mediator reactions, such as plasma serotonin and histamine, and also reduced blood loss by preserving platelets and inhibiting fibrinolysis during CPB.

Recently it has been shown that inhaled nitric oxide (NO), which has been proven to contribute to improvement in critical pulmonary hypertension, may provide a favorable effect early after left ventricular assist device (LVAD) support. To improve right ventricular function, inhalation of NO was added to treatment with conventional catecholamines for four consecutive dilated cardiomyopathy (DCM) patients following institution of LVAD. In two patients 1 hr after inhalation of NO, central venous pressure (CVP), mean pulmonary arterial pressure (PAm), and pulmonary vascular resistance (PVR) were improved. These results led to better LVAD output and resulted in an adequate cardiac index. On the other hand, a right VAD (RVAD) was implemented in one patient whose high CVP, PAm, and PVR continued; he was weaned after 8 days of RVAD support. Another patient who had a high CVP but normal PAm and PVR before and after inhalation of NO had no improvement in his hemodynamic state. These data suggest that inhaled NO may improve systemic circulation by reducing right ventricular afterload and may become a promising and convenient therapy before placing RVAD in DCM patients under LVAD support. RVAD should be conducted in patients with right ventricular failure or when pulmonary hypertension is associated with impaired right ventricular reserve, even after inhalation of NO.

The key to the successful implantation of a left ventricular assist system (LVAS) for patients with end stage cardiac disease is whether the functions of other vital organs are irreversibly damaged or not. The portable cardiopulmonary support system (PCPS) is not only as convenient as, but is more powerful than, the intra-aortic balloon pump (IABP) in resuscitating impaired end organ function. To investigate the efficacy of PCPS in end stage cardiac disease, end organ function before and after the application of PCPS was retrospectively analyzed for end stage cardiac disease. From 1992 to 1996, five cardiomyopathy patients with deterioration in end organ function, despite application of IABP, underwent PCPS support before implantation of LVAS. Urine volume and levels of liver enzymes (sAST and sALT) and serum creatinine were determined before and after institution of PCPS. After the start of PCPS, the urine output increased significantly (1,840 +/- 450-4,340 +/- 470 ml/day, p < 0.01), and levels of sAST, sALT, and serum creatinine decreased significantly (630 +/- 220-150 +/- 50 IU/L, 630 +/- 260-260 +/- 130 IU/L, and 2.9 +/- 0.5-1.2 +/- 0.1 mg/dl, respectively; p < 0.05). All five patients were successfully bridged to LVAS implantation, and none died of multiple organ failure caused by pre-existing cardiac failure. These results indicate that PCPS before LVAS implantation is useful in resuscitating impaired end organ function and improving the survival rate with LVAS implantation for end stage cardiac disease.