Akira Amemiya

Evaluation of leukocyte-depleted terminal blood cardioplegic solution in patients undergoing elective and emergency coronary artery bypass grafting

Leukocyte depletion at reperfusion may have a role in myocardial protection when combined with terminal cardioplegia. We applied this method in a selected group of 68 patients with coronary artery bypass grafting either for elective surgical procedures (n = 38) or emergency surgical procedures with the use of a preoperative intraaortic balloon pump (n = 30) because of developing acute myocardial infarction. Basic cold potassium crystalloid cardioplegic solution was used. During delivery of leukocyte-depleted terminal cardioplegic solution, warm arterial blood delivered from cardiopulmonary bypass was passed through a leukocyte removal filter, mixed with potassium crystalloid cardioplegic solution, and administered to the aortic root for the first 10 minutes of reperfusion. Patients were randomized into three groups for reperfusion: whole blood, terminal cardioplegic solution, and leukocyte-depleted terminal cardioplegic solution reperfusion groups. In elective coronary artery bypass grafting, no significant difference was found in the clinical data. However, in emergency coronary artery bypass grafting, the leukocyte-depleted terminal cardioplegic solution group (n = 10) showed significantly lower peak creatine kinase MB levels (leukocyte-depleted terminal cardioplegic solution versus terminal cardioplegic solution versus whole blood: 27 +/- 11, 56 +/- 13, 74 +/- 18, respectively; p < 0.05) and maximum dopamine doses required at the weaning of cardiopulmonary bypass (6.3 +/- 1.1 versus 11.2 +/- 3.3 versus 9.2 +/- 2.2; p < 0.05) than did the terminal cardioplegic solution (n = 10) and whole blood groups (n = 10). Moreover, the leukocyte-depleted terminal cardioplegic solution group showed significantly lower difference of malondialdehyde between arterial and coronary sinus blood (0.15 +/- 0.09 versus 0.36 +/- 0.06 versus 0.06 +/- 0.12 nmol/ml, p < 0.05) than did the terminal cardioplegic solution or whole blood groups. These results showed that leukocyte-depleted terminal blood cardioplegic solution may have a role in attenuating reperfusion injury in patients with critical conditions such as preoperative myocardial ischemic injury.

Leukocyte depletion attenuates reperfusion injury in patients with left ventricular hypertrophy.

BACKGROUND Reperfusion injury can occur after a long period of aortic cross-clamping in patients with left ventricular hypertrophy during open-heart surgery, even with the most up-to-date techniques of myocardial protection. In the present study, we examined whether leukocyte depletion as an adjunct to terminal blood cardioplegia (LDTC) attenuates reperfusion injury in patients with left ventricular hypertrophy (LV mass, >300 g; left ventricular end-systolic volume index, >100 mL/m2) in a group of 30 patients undergoing aortic valve replacement. METHODS AND RESULTS We used basic cold potassium crystalloid cardioplegic solution. Terminal blood cardioplegic solution (TC) or LDTC was accomplished by mixing a cold potassium crystalloid cardioplegic solution with warm arterial blood obtained through cardiopulmonary bypass and administered to the aortic root for the first 10 minutes of reperfusion. During delivery of LDTC, warm arterial blood was passed through a leukocyte-removal filter. Patients were randomized into one of three groups for reperfusion: whole blood (WB) (n=10), TC (n=10), and LDTC (n=10). Left ventricular biopsies were obtained before ischemia, at the end of ischemia, and 15 minutes after reperfusion. Semiquantitative scoring for ultrastructural alterations indicated that the LDTC group achieved significantly better recoveries of both scores at reperfusion for myocyte damage and for endothelial cell damage of capillaries than did the WB and TC groups. The LDTC group had significantly fewer neutrophils adhering to endothelial cells at reperfusion and a lower level of malondialdehyde derived from myocardium than did the WB and TC groups. Regarding the clinical data, the LDTC group had a lower maximum creatine kinase-MB, a higher percentage of spontaneous defibrillation, a lower pulmonary capillary wedge pressure, and a lower requirement for dopamine that did the WB group, whereas the TC group failed to do better than the WB group. CONCLUSIONS These results demonstrate that leukocyte-depleted reperfusion is potentially beneficial as an adjunct to terminal cardioplegia during cardiac surgery to attenuate reperfusion injury in patients with left ventricular hypertrophy.

New strategy for treatment of MRSA mediastinitis: one-stage procedure for omental transposition and closed irrigation

Mediastinitis due to methicillin-resistant Staphylococcus aureus is a devastating potential complication of cardiac surgery. We treated 4 patients with this condition using a new technique. First we performed an early radical removal of infected tissue and omental transposition with direct primary closure of the sternum and closed continuous irrigation with saline/vancomycin hydrochloride; that was followed by an administration of intravenous antibiotics. We obtained good clinical results, which are reported herein along with the clinical courses.

Effect of a cyclic adenosine monophosphate phosphodiesterase inhibitor, DN-9693, on myocardial reperfusion injury

A new cyclic adenosine monophosphate phosphodiesterase inhibitor, DN-9693, was examined to see whether myocardial reperfusion injury could be reduced in a setting of cardioplegic arrest through its antiaggregation effect on leukocytes. Isolated rabbit heart models with whole blood perfusion were used, and 18 hearts were divided into three groups according to the reperfusion method: control (G-1, n = 5), DN-9693 (G-2, n = 7), and leukocyte depletion (G-3, n = 6). The hearts were subjected to 120 minutes of cold global ischemia under crystalloid cardioplegia followed by 30 minutes of reperfusion. A dose of 20 micrograms.kg-1.min-1 of DN-9693 was administered in G-2, and a leukocyte removal filter was used in G-3 during reperfusion. Ultrastructural changes in mitochondrial injuries, intracellular edema, and capillary injuries of the myocardium showed worse changes in G-1 than in G-2 and G-3. Under microscopic study, the intracapillary leukocyte count was significantly higher in G-1 than in G-2 and G-3. Recovery of rate-pressure product, left ventricular developed pressure, and coronary flow were significantly better in G-2 and G-3 than in G-1. There were no significant differences between G-2 and G-3 for all these indices. These results indicate that reperfusion with leukocyte-depleted blood attenuates reperfusion myocardial injury and DN-9693 has a comparable myocardial protective effect with possible inhibition of leukocyte aggregation.

Noninvasive evaluation of internal thoracic artery and left anterior descending coronary artery anastomotic sites using transthoracic Doppler echocardiography: comparison with coronary arteriography.

OBJECTIVES This study was designed to evaluate anastomotic sites located between the internal thoracic artery and left anterior descending coronary artery using transthoracic Doppler echocardiography, and then to clarify the accuracy of those results by comparison with coronary arteriographic findings. METHODS We examined 35 consecutive patients who had undergone bypass surgery. The echocardiographic examinations were performed within approximately 1 week of follow-up coronary arteriography, which occurred at 4.3 +/- 2.2 months after bypass surgery. We measured the diameter using intraluminal flow signals, and we also measured flow velocity. RESULTS Adequate spectral Doppler recordings of coronary flow in the anastomosis were obtained in 31 (89%) of the 35 study patients. In the normal anastomosis group (n = 25), the diameter and the peak blood flow velocity of the internal thoracic artery and left anterior descending coronary artery were 1.5 +/- 0.3 mm and 2.0 +/- 0.4 mm, and 58 +/- 25 cm/s and 47 +/- 20 cm/s, respectively. Stringed internal thoracic artery was found in 4 patients; the echocardiographic findings revealed a greater amount of information regarding the physiologic state in the area of anastomosis compared with angiographic findings. In a stenotic anastomosis found in 2 patients, the blood flow velocity findings at the anastomotic sites (83 +/- 228 cm/s) were higher than those in normal anastomotic patients (59 +/- 28 cm/s). CONCLUSIONS Transthoracic Doppler echocardiography enabled an effective evaluation of anastomotic sites between the internal thoracic artery and left anterior descending coronary artery in over 80% of our patients. This totally noninvasive method is thought to be reliable and able to provide a greater amount of information, compared with coronary arteriography, regarding the physiologic state of an anastomosis, such as a competitive relationship.

Evaluation of the biocompatibility of a new method for heparin coating of a cardiopulmonary bypass circuit

The biocompatibility of the Terumo (Terumo Corporation, Tokyo, Japan) covalent heparin coating method in a cardiopulmonary bypass (CPB) circuit was evaluated in ex vivo and in vivo experiments. In the ex vivo experiment, fresh human heparinized blood primed both a miniature heparin coated circuit (HCC) and the identical noncoated circuit (NCC), and was circulated simultaneously for 2 hr (n = 6). In the in vivo experiment, 10 rabbits underwent 2 hr of CPB under systemic heparinization (ACT > 400 sec) with HCC (n = 5) and with NCC (n = 5). In the ex vivo study, thrombin/anti-thrombin III complex, thromboglobulin, platelet factor IV, granulocyte elastase, and C3a were significantly lower in the HCC than in the NCC at 60 and 120 min of circulation (p < 0.05). In the in vivo study, platelet counts (percent of value at 10 min of CPB) were significantly higher in the HCC than NCC (HCC:NCC 87 +/- 10:71 +/- 12 at 60 min, 81 +/- 17:56 +/- 16 at 120 min). Scanning electron microscopic examination of the circuits showed less significant adhesion and pseudopod formation of platelets in the HCC than NCC in both ex vivo and in vivo situations. These results demonstrate that this heparin coated CPB circuit provides superior biocompatibility compared with a noncoated circuit by reducing the activation of the coagulation cascade, platelets, leukocytes, and complement.

NITRIC OXIDE GAS INFUSION TO THE OXYGENATOR ENHANCES THE BIOCOMPATIBILITY OF HEPARIN COATED EXTRACORPOREAL BYPASS CIRCUITS

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.

Advantage of earlier thoracoscopic clipping of thoracic duct for post-operation chylothorax following thoracic aneurysm surgery

We report that an earlier thoracoscopic clipping of the thoracic duct was advantageous in a case of post-operation chylothorax that occurred following thoracic aneurysm surgery. A 61-year-old man developed chylothorax on postoperative day 2 following graft replacement of the descending thoracic aorta using a left-sided thoracotomy. Since a replaced graft infection is lethal, earlier thoracoscopic clipping of the thoracic duct through the right side chest wall was indicated. The patient underwent thoracoscopic clipping on postoperative day 7 and was successfully treated. The duration of drainage was 2 days and oral intake was started on the seventh day. From our results, we recommend a thoracoscopic procedure through the opposite (right) side chest wall in the early stage of chylothorax development following thoracic aneurysm surgery.

Minimally invasive surgery for lung cancer with coronary artery disease

We report a 69-year-old woman with lung cancer and severe stenosis in the left anterior descending coronary artery. To perform a curative operation for the lung cancer without myocardial infarction, minimally invasive direct coronary artery bypass and left lower lobectomy with video-endoscopic assistance were performed simultaneously. There was no major complication, and she was discharged at 14 days after the operation. This procedure may be useful and safe for patients with lung cancer and coronary artery disease.

Minimally invasive removal of infected pacemaker lead

A 37-year-old woman with sick sinus syndrome suffered complications with recurring local infection at the generator pocket. Repeated debridement and antibiotic therapy was ineffective. Several attempts to remove leads via the implantation vein by direct traction were unsuccessful. We operated using cardiopulmonary bypass and applied a minimally invasive lower ministernotomy to obtain pleasing cosmetic results. After a right atriotomy, leads were removed. The minimally invasive approach gave satisfactory results, especially cosmetically.