Junichi Murayama

Coronary endothelial damage during off-pump CABG related to coronary-clamping and gas insufflation

OBJECTIVE Although off-pump coronary artery bypass grafting (CABG) has been recognized less invasive than conventional CABG on cardiopulmonary bypass, off-pump CABG may be partly invasive especially to the coronary endothelium. The present study was designed to evaluate the adverse effects of coronary snaring with looped sutures and gas insufflation on the coronary endothelium. The protective efficacies on the coronary endothelium of coronary snaring with elastic sutures or humidified gas insufflation with/without heparin and dipyridamole-added were also tested. METHODS Thirty-six mongrel dogs were used. After systemic heparinization (150 U/kg), a 5 mm longitudinal coronary incision was made with looped non-elastic monofilament sutures or elastic sutures applied proximally and distally. The incised coronary artery was exposed to non-humidified carbon dioxide, humidified carbon dioxide with lactated Ringer solution, or humidified carbon dioxide with heparin and dipyridamole-added lactated Ringer solution for 10 or 20 min in each group. After gas insufflation, the incised coronary artery was repaired, then, the coronary was reperfused. Perfusion-fixation was done for observation of the coronary endothelium by scanning electron microscopy. The adverse effect on the endothelium was graded as follows: grade 1, appeared normal; grade 2, few blood cells deposited; grade 3, many blood cells deposited; grade 4, few endothelial cells delaminated with blood cells deposited; grade 5, many endothelial cells delaminated with blood cells deposited. RESULTS Non-elastic looping caused much more endothelial tears than elastic looping (P<0.00001). Non-humidified gas blowing for 20 min caused more endothelial cell damage than humidified gas blowing (P=0.00005). Non-humidified gas blowing for 10 min caused less damage than for 20 min (P=0.00326), but still caused more damage than humidified gas blowing (P=0.00253). Heparin and dipyridamole-added humidification reduced coronary endothelial area mottled by the deposited cells when compared with simple humidification (P=0.00120). CONCLUSIONS Coronary snaring resulted in coronary endothelial injury, which was ameliorated by using elastic sutures instead of non-elastic sutures. Non-humidified gas insufflation made blood cells deposited and endothelial cells delaminated with time. Humidified gas insufflation attenuated these adverse effects. Heparin and dipyridamole-added humidification had potential advantage in terms of reducing deposited blood cells on the endothelium over simple humidification.

Splenic abscess associated with active infective endocarditis

Splenic abscess is a rare complication in infective endocarditis. Here, we present two cases of splenic abscess associated with active infective endocarditis. Body computed tomography before emergency valvular surgery revealed abscess in the spleen. In case 1, the abscess was localized within the spleen; splenectomy and valve replacement were performed through the same median skin incision. In case 2, the splenic abscess was diagnosed as ruptured; valve replacement was performed, followed by splenectomy through a separate skin incision. No recurrence of infection occurred after surgery in either case. In surgical treatment for active infective endocarditis, body computed tomography is essential to diagnose splenic abscess preoperatively. If there is an abscess, then splenectomy and valvular surgery should be performed simultaneously to prevent reinfection after valvular surgery. The approach to the spleen should be individualized according to the extension of the abscess.

Surgical Revascularization for Acute Coronary Syndrome : Comparative Surgical and Long-term Results

OBJECTIVE The purpose of this study was to evaluate the adequate timing of coronary artery bypass grafting (CABG) for acute coronary syndrome (ACS). METHODS In our institution, emergency CABG has been avoided when possible for ACS patients favoring stabilization with medical therapies, including intra-aortic balloon pumping or percutaneous coronary intervention. After thorough preoperative examinations, an urgent CABG is performed. A total of 67 patients with ACS underwent CABG, comprised of 33 patients receiving an emergency CABG (emergent group: E-G) and 34 patients receiving an urgent CABG (urgent group: U-G). The early and long-term results were evaluated retrospectively. RESULTS Preoperatively, the incidences of acute myocardial infarction and cardiogenic shock were significantly higher in E-G. No significant differences were found in the intraoperative factors except for the number of distal anastomoses (2.5 in E-G vs. 3.1 in U-G, p=0.01). The hospital mortality was 9.1% in E-G, and 2.9% in U-G, with no significant difference between the groups. Moreover, no patient in U-G necessitated emergency CABG while waiting for surgery. The patency rate of the grafts was 100% in E-G, and 96.2% in U-G. The 5-year survival rate excluding in-hospital death was 80.3% in E-G, and 78% in U-G (p>0.05). The 5-year cardiac event-free rate was 80.3% in E-G, and 80.9% in U-G (p>0.05). CONCLUSION An emergency CABG can be reserved for ACS patients when symptoms and hemodynamic state are stabilized with medical therapies. Improvements in long-term results can be expected after high quality and complete surgical revascularization.

Nicorandil attenuates reperfusion injury after long cardioplegic arrest.

The cardioprotective efficacy of nicorandil in cardiac surgery was determined using a surgically relevant 4-hr cardioplegic arrest model. Each isolated rabbit heart was parabiotically blood-perfused using a modified Langendorff column. The magnitude of left ventricular developed pressure and rate of change of developed pressure over time were measured before (baseline) and after ischemia. Nicorandil was administered either pre-ischemia, post-ischemia, pre/post-ischemia, or continuously (before, during, and after ischemia). The endothelium of the coronary artery was observed by scanning electron microscopy. Serum myeloperoxidase activities were also measured. Although pretreatment with nicorandil did not affect recovery of developed pressure, administration of nicorandil after ischemia, or before and after ischemia, enhanced the recovery of developed pressure. Serum myeloperoxidase activity was decreased in the pre/post-ischemia and continuous groups. Endothelial reperfusion injury decreased in all nicorandil-treated groups. Administration of nicorandil attenuated ischemia-reperfusion injury of the myocardium and coronary endothelium while ameliorating leukocyte activation. In the event of unexpected prolonged cardioplegic arrest, administration of nicorandil, even just after declamping, may improve cardiac function. However, pre-ischemia administration alone was not helpful in the heart subjected to prolonged cardioplegic arrest.

Complete rupture of the posterior papillary muscle caused by late reperfusion for acute myocardial infarction

We describe a patient with acute mitral regurgitation due to complete rupture of the papillary muscle immediately after successful late reperfusion for inferior myocardial infarction. An 81-year-old woman was admitted complaining of mild chest discomfort. Although the electrocardiograms, biochemical test results, and her clinical history showed that several days had passed since the onset of acute myocardial infarction, a late coronary stenting was performed. Immediately after successful stenting, she suddenly developed acute pulmonary edema, leading to cardiogenic shock. In addition to high pulmonary capillary wedge pressure (mean 35 mmHg), color Doppler imaging revealed massive mitral regurgitation caused by complete rupture of the posterior papillary muscle. Emergent mitral valve replacement with a prosthetic valve was performed, saving the patient. Hence, late reperfusion should be considered carefully when treating a patient with a high risk, such as an elderly patient or a patient with single-vessel disease or initial transmural myocardial infarction.

Mitral Annular Reconstruction

Mitral annular reconstruction using a pericardial patch was performed in 3 cases of atrioventricular disruption. This technique may be useful for atrioventricular disruption in cases of active endocarditis, redo valve replacement, left ventricular rupture after mitral valve replacement, and annular calcification.

Aorto-Left Renal Vein Fistula Caused by a Ruptured Abdominal Aortic Aneurysm

Retroaortic left renal vein is a malformation in which the left renal vein courses dorsal to the abdominal aorta. In patients with abdominal aortic aneurysm, an aorto-left renal vein fistula can form if the left renal vein is sandwiched between the aneurysm wall and lumbar vertebrae. The patient was an 84-year-old man with lower back pain. We performed a contrast-enhanced computed tomography (CT), although renal dysfunction was noted. The CT showed a ruptured juxta-renal abdominal aortic with aorto-left renal vein fistula. This clinical condition can cause severe renal dysfunction, in spite of which an enhanced contrasted CT scan would be extremely informative preoperatively.

Surgical Treatment for a Trauma-Caused Cardiac Rupture

鈍的外傷による心破裂の救命率は低い.救命率の向上のためには診断,治療方針を明確にする必要がある.われわれは鈍的外傷による心破裂例8例を経験した.来院時,全例経胸壁心エコーにより心嚢液貯留を認め,心タンポナーデの状態であった.受傷から来院までの平均時間は186±185分,来院から手術室搬入までの平均時間は82±49分.術前に心嚢ドレナージを行ったのは2例,経皮的心肺補助装置を使用したのは2例であった.破裂部位は,右房3例,右房-下大静脈1例,右室2例,左房1例,左室1例であった.4例に体外循環を用い損傷部位を修復した.8例中6例を救命することができた(救命率75%).診断において経胸壁心エコーが簡便かつ有効であった.多発外傷例が多いが,心タンポナーデによるショック状態を呈している場合,早急に手術室へ搬送すべきである.手術までの循環維持が重要であり,心嚢ドレナージ,PCPSが有効である.

Mitral Valve Repair in an Adult Case of Marfan's Syndrome

孤立性僧帽弁閉鎖不全症を呈したMarfan症候群の38歳女性に対し弁形成術を施行し良好な結果を得たので報告する.20歳ごろより僧帽弁閉鎖不全症を指摘されており3ヵ月前から息切れが出現.僧帽弁後尖の著明な逸脱によるIV度の僧帽弁閉鎖不全症を認め,左室拡張末期径は60mmと拡大していた.術中所見にて僧帽弁後尖は全体的にredundantで逸脱しており逸脱部を2ヵ所,矩形に切除した.後尖が高く術後の前尖収縮期前方運動が危惧され,弁尖基部を楔形に切除し,sliding leaflet techniqueを用いて弁尖を縫合したのち,人工弁輪を縫着した.術後,僧帽弁閉鎖不全症は消失し,左室拡大の改善を認めた.現在,術後3年経過しているが僧帽弁閉鎖不全症の再発を認めていない.成人Marfan症候群に伴う孤立性僧帽弁閉鎖不全症に対しては,対象症例が比較的若年であり,遠隔期の大動脈病変に対する手術の可能性が高いため,弁形成術を積極的に施行すべきである

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.