Hyperchloremic acidosis develops at the stage G4 and shifts to high anion gap acidosis at the stage G5 in chronic kidney disease.

BACKGROUND: Amelioration of hyperchloremic acidosis (Cl-Ac), a common complication in chronic kidney disease (CKD), could preserve renal function in chronic kidney disease (CKD). However, the development of Cl-Ac in CKD has not been clarified yet. METHODS: The degree of Cl-Ac, which is indicated as the bicarbonate concentration decrease with serum chloride concentration increase (∆[HCO3-]Cl), was compared with the estimated glomerular filtration rate (eGFR) by using CKD patient records. RESULTS: In 307 records with metabolic acidosis, a spline curve obtained from the plot comparing ∆[HCO3-]Cl with eGFR showed that ∆[HCO3-]Cl did not change, increased, and decreased during eGFR decrease until 27, from 27 to 17.5, and from 17.5 mL/min/1.73 m2, respectively. CONCLUSION: By CKD progression, Cl-Ac progressed and regressed at the CKD stages G4 and G5, respectively. The regression would have reflected the shift of Cl-Ac to high anion gap acidosis.

[Impending Paradoxical Embolism with Acute Pulmonary Embolism during Postural Change;Report of a Case].

A state in which thrombus is found in both right and left atria with thrombus penetrating the foramen ovale is called as impending paradoxical embolism (IPE). A 42-year-old man was found to have poor oxygenation and shock when his body was turned prone after induction of anesthesia. We inserted percutaneous cardiopulmonary support (PCPS), and his blood pressure was maintained. Transesophageal echocardiography revealed right heart pressure overload and left atrial thrombus. Computed tomography (CT) showed thrombosis in both main pulmonary arteries. The patient was judged to require emergency surgery. Bilateral pulmonary artery thrombus and thrombus between the right and left atria was removed under hypothermia using a heart-lung machine. Postoperatively, thrombus was detected in the bilateral posterior tibial vein and peroneal vein. He had a good postoperative course. There were few reports of IPE with pulmonary embolism that developed during operation.

Influence of Hemofiltration on Intradialytic Plasma Volume Decrease.

BACKGROUND/AIMS: Compared with hemodialysis (HD), hemodiafiltration (HDF) reduces the frequency of episodes of intradialytic hypotension. Intradialytic plasma volume decrease (IPVD) induced by ultrafiltration is a leading cause of the episodes, and hemofiltration might have a preventive effect on IPVD. This study examined whether online HDF (ol-HDF) prevented IPVD compared with HD. METHODS: Online HDF of pre-dilution mode (pre-ol-HDF) and post-dilution mode (post-ol-HDF) and HD were performed in 22 patients on maintenance dialysis. In each session, IPVD was calculated by using an intradialytic change in hematocrit, and IPVD in pre-ol-HDF and post-ol-HDF was compared with that in HD in a crossover manner. RESULTS: While the ratios of intradialytic body weight loss to post-dialysis BW (IBWL/BW) in ol-HDF were generally smaller than those in HD, the levels of IPVD and IPVD/IBWL/BW were generally larger than those in HD; the IPVD levels were 0.108 ± 0.058, 0.113 ± 0.053, and 0.101 ± 0.057 (P = 0.67), and those of IPVD/IWL/BW were 2.21 ± 0.97, 2.32 ± 0.91, and 1.98 ± 1.14 (P = 0.21) in pre-ol-HDF, post-ol-HDF, and HD, respectively. CONCLUSION: Online mode hemofiltration, in either pre-dilution mode or post-dilution mode, performed in combination with hemodialysis has no preventive effect on IPVD.

[Primary cardiac leiomyosarcoma originating from the left atrium].

Primary malignant cardiac tumors occur extremely rarely. Among these, leiomyosarcomas are exceptionally rare. We described a case of left atrial leiomyosarcoma in which surgical intervention was followed by adjuvant radiation therapy. A 74-year-old male was admitted for dyspnea. Chest X-ray showed severe pulmonary congestion. Echocardiography revealed large tumor in the left atrium. Emergency operation was performed. The tumor invaded the left atrial wall and the mitral valve, and the lesion was resected as extensively as possible. Postoperative pathologic examination confirmed leiomyosarcoma. He underwent adjuvant radiotherapy postoperatively. However, early local recurrence was recognized. He died due to sudden circulatory collapse in 8th postoperative month. As cardiac leiomyosarcomas have extremely poor prognosis, complete resection and effective postoperative adjuvant therapy are necessary.

Misdiagnosis of high anion gap acidosis owing to instrument error of a device.

The anion gap (AG) is a tool to diagnose metabolic acid-base disorders in the physiological approach to acid-base assessment. It is used to detect high AG acidosis, a type of metabolic acidosis caused by serum concentration increase in usually unmeasured anions; AG larger than the reference for it indicates the presence of high AG acidosis. This report presents a case of hyperlactatemia which was not detected as high AG acidosis possibly because of instrument error of a device in measurement of serum sodium and chloride concentrations. The case indicates that the error will make AG unable to detect high AG acidosis of any cause. Hence, upon suspicion of high AG acidosis caused by measurable anions such as lactate and ketones, it is recommended to measure their serum concentration.

Partial aortic root remodelling for fistula between the non-coronary sinus and the right atrium.

This report describes a rare case of the fistula between the non-coronary sinus and the right atrium (RA) after ascending aortic replacement for chronic aortic dissection. A 67-year-old lady had been suddenly suffering from severe dyspnoea with general fatigue for a couple of days. Trans-thoracic echocardiogram in the emergency room demonstrated massive shunt flow from the non-coronary sinus to the RA with remarkable dilatation of the RA, right ventricle (RV) and inferior vena cava, similar to the rupture of sinus of Valsalva (Konno-type IV). The fistula was successfully treated by partial remodelling of the aortic root in an emergency basis because of her life-threatening illness. Some remaining diseased aortic root, which may be related to initial dissection or inappropriate use of gelatin-resorcin-formalin glue at the previous ascending aortic replacement, may cause this kind of serious events. Modified aortic root remodelling method with only diseased sinus resected was successfully applied to the localised aortic root disorder.

Configurations of the mitral valve during off-pump coronary artery bypass grafting: endoscopic and three-dimensional analysis.

BACKGROUND AND AIM OF THE STUDY: During off-pump coronary artery bypass grafting (CABG), mitral regurgitation (MR) has been experienced in relation to the procedures. The study aim was to evaluate the mitral valve configuration, with particular focus on annular behavior, during off-pump CABG, using cardiac endoscopy and digital 3-D ultrasound sonomicrometry. METHODS: Following implantation of six crystals of the digital 3-D ultrasound sonomicrometer around the mitral annulus, and two crystals on the epicardial base of the papillary muscles, off-pump CABG was simulated in seven beagle dogs. The heart was perfused with pellucid Krebs-Henseleit solution in situ, with controlled left ventricular end-diastolic pressure (LVEDP). The behaviors of the mitral annulus and leaflets were then observed endoscopically with only cardiac displacement, 15 min occlusion of the left anterior descending artery (LAD), or 15 min occlusion of the left circumflex artery (LCx) with cardiac displacement. Dimensions between the crystals were also recorded using digital 3-D ultrasound sonomicrometry. RESULTS: With only cardiac displacement, no MR was observed endoscopically, and no major changes occurred in annular configuration when coronary perfusion was maintained. In one dog, MR was observed only from the anterolateral site after LAD occlusion. MR from the posteromedial site was observed by occlusion of the LCx in all cases, with significant (p < 0.01) enlargement of the mitral annular dimensions. CONCLUSION: Cardiac displacement alone did not cause MR if coronary perfusion was maintained. Occlusion of the LAD rarely caused MR from the anterolateral site, whereas occlusion of the LCx normally caused MR from the posteromedial site; the posteromedial annulus was enlarged, even when the LVEDP was controlled.

Direct imaging of bileaflet mechanical valve behavior in the tricuspid position.

OBJECTIVE: The optimal orientation of a bileaflet mechanical valve for tricuspid valve replacement (TVR) has not yet been determined. The aim of this study was to use fiberoptic cardioscopy to evaluate the effect of orientation of a mechanical valve implanted in the tricuspid position on bileaflet mechanical valve behavior. METHODS: Twelve pigs (50-59 kg) underwent TVR with a St. Jude Mechanical Heart Valve (25 mm standard cuff model) after cardioplegic arrest. The mechanical valve was implanted horizontally in six pigs (Group H), and vertically in another six pigs (Group V). The heart was perfused with pellucid Krebs-Henseleit solution in situ and the mechanical valve behavior was observed with a fiberoptic endoscope during different heart rates (HRs) induced by ventricular pacing (60, 90, 120, 150 min(-1)). All images were recorded on a high-speed video system every 4 ms. The closing time lag (CTL) between the valve leaflets was calculated and compared between the two groups. RESULTS: In Group H, the lower valve leaflet tended to open incompletely and close earlier than the upper leaflet. The calculated CTL was 303+/-60 ms, 65+/-48 ms, 40+/-9 ms, and 40+/-26 ms at pacing HRs of 60, 90, 120, and 150 min(-1), respectively. In contrast to Group H, there was little difference in CTL between the right and left leaflets in Group V. The calculated CTL was 9+/-12 ms, 11+/-10 ms, 1+/-3 ms, and 6+/-7 ms at pacing HRs of 60, 90, 120, and 150 min(-1), respectively. There were significant differences in CLT between the two groups at each ventricular pacing rate (P < 0.01). CONCLUSIONS: Orientation of an implanted bileaflet valve in the tricuspid position significantly influenced leaflet motion. In a horizontal orientation, the lower valve leaflet opened incompletely and closed earlier than the upper leaflet. These results suggest that the gravity might affect leaflet motion and that bileaflet mechanical valves should be implanted vertically in TVR to prevent abnormal leaflet motion and thrombus formation.

Chronic contained rupture of aortic aneurysm with thoracic vertebral erosion.

A 66-year-old man was transferred to our hospital with the diagnosis of a large thoracoabdominal aneurysm. Computed tomography showed thoracic vertebral erosion, suggesting a chronic contained rupture. He was hemodynamically stable with no neurological complication preoperatively. He underwent successful surgical replacement of the descending aorta. During surgery, the 6th and 7th thoracic vertebral bones adjacent to the thoracic aneurysm were found to be eroded. The postoperative course was uneventful.

Evaluation of native valve-sparing aortic root reconstruction with direct imaging--reimplantation or remodeling?

BACKGROUND: Aortic root reimplantation and remodeling have been used to preserve the native aortic valve. However, direct observation of valve motions with these techniques has not been performed. METHODS: Mongrel dogs were studied. The beating heart model was created using modified Tyrode's solution. Normal aortic valves and aortic valves preserved with the remodeling or reimplantation procedure were observed with an endoscope, and behavior was recorded on a high-speed video (200 frames/s). The aortic valve orifice area was measured at 11 data points per beat. A predictable maximum valve orifice area was defined as an area encircled by the three commissures. A ratio of each aortic valve orifice area to the predictable maximum valve orifice area was calculated. The control group, the reimplantation group, and the remodeling group were compared. RESULTS: The preserved aortic valve with reimplantation showed bending and asymmetric motion. The ratio of aortic valve orifice area and predictable maximum valve orifice area in the reimplantation group was significantly smaller compared with the control and remodeling groups. CONCLUSIONS: The opening and closing behavior of the aortic valve preserved with the reimplantation procedure was impaired. It was speculated that the remodeling procedure may preserve more physiologic root function compared with the reimplantation procedure.

Surgical results of hemiarch replacement for acute type A dissection.

BACKGROUND: The appropriate surgical strategy for patients with an arch tear in acute type A dissection remains controversial. We retrospectively compared surgical results after hemiarch as compared with transverse aortic arch replacement in patients with an arch tear in acute type A dissection. METHODS: The records of 88 patients who consecutively underwent graft replacement for acute type A dissection between 1989 and 2001 were reviewed. The patients were divided into three groups: patients with ascending aortic replacement (group AS, n = 41), those with hemiarch replacement (group HA, n = 23), and those with transverse arch replacement (group AR, n = 24). Operative mortality and morbidity and late outcome were compared among the three groups. RESULTS: The overall early (30 day) mortality was 11.3% (10/88), and in-hospital mortality was 14.7% (13/88). In-hospital mortality in groups AS, HA, and AR were 7.3%, 8.6%, and 33.3%, respectively (p = 0.011). Cardiopulmonary bypass, circulatory arrest, and operation times were significantly shorter in group HA than in group AR (p < 0.001). A smaller amount of intraoperative transfusion of red blood cells (p = 0.0006) and fresh-frozen plasma (p = 0.0003) was needed in group HA than in group AR, and postoperative bleeding during the first 24 hours postoperatively was significantly less in group HA than in group AR (p = 0.0028). The incidence of postoperative coma did not differ among the three groups (p = 0.89), nor did the incidence of postoperative patent false channel in the descending thoracic aorta (p = 0.57). Actuarial survival rates after 5 years were significantly better in group HA (91.3% +/- 5.9%) than in group AR (44.4% +/- 14.3%, p = 0.018). Freedom from reoperation on the distal aorta within 5 years did not differ among the groups (p = 0.46). CONCLUSIONS: Hemiarch replacement for acute type A dissection demonstrated favorable early and late outcome. The extent of graft replacement influenced surgical mortality and morbidity. Whenever the intimal tear is located in the lesser curvature of the transverse arch, hemiarch replacement is recommended to improve overall operative mortality and morbidity.

Distensibility of the pulmonary autograft under systemic pressure.

BACKGROUND AND AIMS OF THE STUDY: Although the Ross procedure has recently been recognized as one of the best replacements of the aortic valve, regurgitation has occasionally been observed with dilatation of the sinotubular junction (STJ) and/or basal ring (BR). This study was designed to evaluate the native distensibility of the free pulmonary root under systemic pressure. METHODS: Pulmonary arterial grafts (n = 7) were taken from pig hearts and pressurized (20-100 cmH2O) with crystal sensors attached around the STJ and BR. Dimensions of the STJ and BR were measured using a digital 3-D ultrasonic sonomicrometer at different pressures (20-100 cmH2O) with and without the STJ and/or BR plicated with felt-strip to prevent overdistension. Valve insufficiency was evaluated macroscopically and endoscopically. RESULTS: All grafts showed no obvious valve insufficiency at 20 cmH2O. Grafts pressurized at 100 cmH2O showed 125+/-6% and 113+/-5% enlargement of dimensions compared with baseline (20 cmH2O) data at the STJ and BR respectively, with recognizable insufficiency. When the STJ was plicated to prevent overdistension at 100 cmH2O with less dilated BR (106%), mild excentric insufficiency was observed. In case of the BR plicated at 100 cmH2O with a less dilated STJ (112%), central slight regurgitation was observed. Both the STJ and BR plications resulted in no recognizable regurgitation. CONCLUSION: Free pulmonary arterial grafts were remarkably enlarged under systemic pressure with recognizable valve insufficiency; this could be prevented by maintaining the original dimensions of the graft STJ and BR.

Heparinless cardiopulmonary bypass with argatroban in dogs.

OBJECTIVES: Systemic heparinization is usually required for cardiopulmonary bypass (CPB). However, problems such as heparin-induced thrombocytopenia, protamine shock, and antithrombin III deficiency exist related to CPB with heparinization. The aim of this study was to evaluate argatroban (ARG) as a substitute for heparin during CPB. METHODS: In the pilot study, blood samples were sequentially obtained from dogs with continuous infusion of ARG at a dose of 10 (n = 6), 20 (n = 6), or 30 (n = 6) microg/kg per min for 2 h without CPB. In the main study, dogs underwent CPB for 2 h with 10 (n = 6) or 30 (n = 6) microg/kg per min of ARG or with heparin with blood samples obtained sequentially. Thrombogenicity in each group was evaluated by observation of the blood-contacting surfaces of the CPB circuits with scanning electron microscopy (SEM). Evidence of thromboembolism in the dogs was also investigated in histological specimens of the kidney and spleen in addition to microscopic observation at autopsy. RESULTS: In the pilot study, the activated coagulation time (ACT) reached a maximum level dose-dependently after continuous infusion of ARG for 30 min. ACT returned to the baseline value within 60 min after the termination of continuous infusion. In the main study, CPB with 30 microg/kg per min of ARG achieved thrombin-antithrombin III complex (TAT) level similar to that achieved by CPB with heparin. Platelet count with 30 microg/kg per min of ARG tended to be higher than that with heparin or 10 microg/kg per min of ARG. The SEM appearance of blood-contacting surfaces of the CPB circuits after infusion with 30 microg/kg per min of ARG appeared to be similar to that after infusion with heparin. Depositions on the blood-contacting surfaces of the CPB circuits were also frequently observed with 10 microg/kg per min of ARG. CONCLUSIONS: Coagulability related to CPB was controlled by the appropriate ARG dosage without the use of heparin in dogs. ARG may be a substitute for heparin in CPB.

Successful management of acute pulmonary embolism after surgery for lung cancer.

OBJECTIVE: Although many case reports of acute pulmonary embolism (APE) have been published, the literature dealing with the management of APE after resection of lung cancer is limited. This report describes seven cases of successful management of APE after surgery for lung cancer and discusses how to manage this problematic complication. METHODS: The medical charts of seven patients with APE after lobectomy and complete mediastinal lymphnode dissection were retrospectively reviewed. RESULTS: Six patients collapsed during their first attempt at walking after surgery in conjunction with a dramatic respiratory change. All these patients promptly underwent enhanced spiral computed tomography (CT) scanning. Bilateral clots were detected in all patients and one patient with a deep venous thrombus (DVT) in the femoral vein had a temporary inferior vena cava filter implanted. Non-surgical therapy was used for six patients: thrombolysis (systemic urokinase) and anticoagulant (heparin or argatroban) for four patients and only anticoagulant therapy started on the day after the operation using argatroban for two. There were no bleeding problems with these thrombolysis and/or anticoagulant therapies except in one case of hemorrhage induced by heparin usage on the day after the operation. None of the cases required allotransfusion in connection with these therapies. Thromboembolectomy was performed for one patient who was hemodynamically unstable due to massive embolism and primary atrial fibrillation. All patients were discharged from our hospital without major complications. CONCLUSIONS: Patients with pulmonary embolism after surgery for lung cancer can be treated aggressively with anticoagulants with/without fibrinolitics or even with pulmonary embolectomy on cardiopulmonary bypass, without excessive risk of bleeding complications. Enhanced spiral CT scanning was very helpful for making a simultaneous diagnosis of APE and DVT. The use of argatroban in conjunction with activated clotting time monitoring should be effective without causing bleeding problems during the early stages after pulmonary resection for lung cancer.

Clinical Use of Centrifugal Pumps and the Roller Pump in Open Heart Surgery: A Comparative Evaluation.

Centrifugal pumps have been used widely as the main pump in open heart surgery to reduce damage to blood elements and to reduce the activation of the coagulation system. The purpose of this study was the evaluation and comparison of the effects of two types of centrifugal pumps and of one type of roller pump on blood elements, the coagulation system, complements, and immunoglobulins. Two types of centrifugal pumps (Lifestream; St. Jude Medical, Chelmsford, Massachusetts; and BP-80; Medtronic, BioMedicus, Inc., Eden Prairie, Minnesota, U.S.A.) and one roller pump (Mera Co.) were used separately as the main pump for cardio-pulmonary bypass (CPB) in 29 patients. Platelet counts, lactate dehydrogenase, antithrombin III, thrombin-antithrombin complex (TAT), complements (C3, C4, and CH50) and immunoglobulins G, A, and M values were measured before and after CPB and compared. Values, except those for TAT, showed no significant difference among the three groups. The TAT values increased less in each of the centrifugal pump groups than in the roller pump group. This finding suggests that thrombin synthesis might be suppressed by the use of a centrifugal pump.

Geometrical difference between an ascending aneurysm and a root aneurysm in valve-sparing operations.

OBJECTIVE: The aortic root geometry of the leaflet size and coaptation in an ascending aortic aneurysm, and in a root aneurysm, may predict the early and late outcomes from valve-sparing surgery. METHODS: The aortic root was investigated using intraoperative endoscopy before and after valve-sparing root reconstruction. The definition of 'root aneurysm' was marked sinus dilatation proximal to the sinotubular junction. 'Ascending aneurysm' was defined as dominant dilatation distal from the sinotubular junction. Fifteen cases were examined and classified into two groups; Group A with an ascending aneurysm (four patients), and Group R with a root aneurysm (eleven patients). RESULTS: Cusp prolapse was seen in 10 (90.9%) patients of Group R, and in only one (25%) patient of Group A. The length of the free margin of all cusps in Group R was significantly longer than those in Group A. In Group R, the lengths of the free margin of an individual cusp were significantly different, indicating asymmetric cusps. In Group A, the length of the free margin were similar, indicating symmetric cusps. There was no significant difference in the degree of immediate postoperative aortic insufficiency, between the two groups. At the most recent follow-up, progressive aortic insufficiency was present in two patients of Group R. CONCLUSIONS: A root aneurysm had asymmetric, elongated and prolapsed aortic cusps, while an ascending aneurysm had symmetric cusps without prolapse. The mechanism of aortic insufficiency in a root aneurysm was more complex, suggesting a difficulty in achieving long-term valve competence. Such geometrical difference should be considered in the indication for the surgical technique of valve-sparing operations.

Improved survival of surgery for acute type A aortic dissection: impact of noninvasive diagnosis and hemostatic surgical management.

OBJECTIVES: In the past decade, progress in cardiovascular technology has been incorporated into the surgical treatment of acute type A dissection resulting in remarkable improvement. Factors in this progress encompass rapid noninvasive diagnosis, intraoperative introduction of aprotinine, surgical glue, sealed grafts, and refined surgical technique. The objective of this study is to identify which factors contributed to the improvement of the surgical outcome of acute type A dissections. METHODS: Between January 1989 and February 2001, 78 consecutive patients had emergency surgeries for acute type A dissection. The initial 31 patients (group I) received preoperative angiography, when possible. Since 1996, the next 47 patients (group II) have received noninvasive rapid diagnosis with hemostatic surgical management. This included aggressive proximal resection and judicious use of gelatin resorcine formol glue and felt strips. Between the two groups, in-hospital mortality and morbidity, incidence of neurological complications, late survival and cardiovascular events were compared. Risk factors for in-hospital death were investigated with univariate and multivariate analysis. RESULTS: The in-hospital mortality was significantly improved in group II (4.3%) compared with group I (29.0%). Overall mortality was 14.1%. Multivariate analysis revealed preoperative limb ischemia and delayed timing of operation (> 3 hours after arrival) as independent risk factors for in-hospital death. Late survival at 5 years was 61.5+/-7.5%. Between the two groups there was no significant difference in late survival or cardiovascular events. CONCLUSIONS: Immediate surgical intervention, using rapid noninvasive diagnosis with hemostatic management, substantially improves the surgical outcome of acute aortic dissection.

Coronary occlusion using bi-directionally stretched elastic sutures during off-pump coronary artery bypass grafting.

OBJECTIVE: Off-pump coronary artery bypass grafting may be partly invasive, particularly to the coronary endothelium that is snared. Efficacy of a simple technique to occlude a coronary artery with elastic sutures bi-directionally stretched just beneath the artery was evaluated. METHODS: Test subjects were eighteen adult mongrel dogs weighing 20-30 kg. After systemic heparinization (150 U/kg), the mid-left anterior descending artery (mid-LAD) was exposed with a stabilizer applied and snared using non-elastic sutures (n = 6) or elastic sutures (n = 6), or occluded with elastic sutures bi-directionally stretched (n = 6). The left internal thoracic artery (LITA) was anastomosed to the mid-LAD with humidified gas insufflation. After completion of the anastomosis, the mid-LAD was observed endoscopically through the LITA. The coronary endothelium was also observed by a scanning electron microscope (SEM) after perfusion fixation. RESULTS: Bleeding at the anastomotic site with the coronary artery occluded by bi-directionally stretched elastic sutures was observed. However, all anastomoses were done successfully with the aid of humidified gas insufflation. Coronary endoscope showed that the lumens snared with non-elastic sutures were collapsed with folds and often with clots. Coronary arteries snared with elastic sutures appeared similar to the arteries snared with non-elastic sutures endoscopically, but with less clots. In the case of coronary occlusion with bi-directionally stretched elastic sutures, the lumens were occluded in a flattened linear fashion without clots. SEM showed endothelial injuries with blood cells deposited when non-elastic sutures were used. When elastic sutures were used for snaring, endothelial injuries were ameliorated with less blood cells deposited, which were further decreased when elastic sutures were bi-directionally stretched. CONCLUSION: The coronary artery can be effectively occluded by bi-directionally stretched elastic sutures with minimal endothelial damage.