Tatsuo Fujiki

Off-pump coronary artery bypass for a heparin-allergic patient

A 46-year-old man with no history of drug allergy developed acute myocardial infarction. Coronary angiographic findings revealed triple vessel disease. Serum hepatic enzymes were elevated due to heparin administered to control infarction, and an allergic reaction developed exclusively due to heparin. To avoid heparin use, we adopted heparin-free off-pump coronary artery bypass grafting through median sternotomy. The systemic anticoagulant agent argatroban was administered to maintain active clotting time over 200 seconds. The left internal thoracic artery was anastomosed to the left anterior descending artery, the radial artery to the diagonal branch, and the right gastroepiploic artery to the right coronary artery. Patency was confirmed by postoperative coronary angiography. No complications were noted. For patients with heparin allergy, off-pump coronary artery bypass grafting is a useful maneuver, because it can be conducted using anticoagulant agents other than heparin.

Epicardial pulmonary vein isolation with a hook-shaped cryoprobe to treat atrial fibrillation.

PURPOSE After it was shown that a rapidly firing focus in a pulmonary vein (PV) can cause atrial fibrillation, percutaneous endocardial PV isolation using radiofrequency began to be used as a method of treatment. However, this technique is time consuming. It requires fluoroscopy and contrast media to identify the PV, and cardiac tamponade and PV obstruction are major complications. To overcome these drawbacks, we developed a hook-shaped cryoprobe to enable circumferential ablation of PV orifices epicardially. The aim of this experimental study in dogs was to confirm the efficacy of this method electrophysiologically. DESCRIPTION Five mongrel dogs (32 PVs) were used. Surrounding tissue was dissected to expose all PVs and their orifices into the left atrium. Each PV was stimulated with an electrode to measure the length of PV which has the same pacing threshold as the left atrium. EVALUATION The mean distance from the PV orifice to the pacing boundary line was 8.9 +/- 1.3 mm. Encircling cryoablation was performed with a hook-shaped cryoprobe to circumferentially ablate each PV orifice epicardially. CONCLUSIONS Cryoablation by this method created a bidirectional conduction block in all PVs. All PVs were electrically isolated, and the PV isolation was achieved epicardially without atriotomy. This method should enable less invasive treatment of AF clinically.

Late leaflet fracture and embolization of a Duromedics mitral prosthesis

A case of leaflet fracture and embolization of a mitral prosthetic valve is described. A 54-year-old man had received mitral valve replacement with an Edwards-Duromedics 29M prosthetic valve, at 10 years ago. Emergency mitral valve replacement was performed because the patient had severe congestive left heart failure with severe acute mitral regurgitation caused by a fracture in one of the mitral valve leaflets. The leaflet, which was fractured into 2 pieces, was removed from the right common iliac artery at 3 months after valve replacement. Visual inspection revealed that the leaflet contained a midline fracture. The fracture originated within a cavitary erosion pit near the major radius of the leaflet. The patient recovered from acute renal failure, requiring hemodialysis for 80 days, and is currently without complaints. We have used a Duromedics mitral valve in 11 patients, from April 1987 to April 1988. No subsequent valve failure has occurred. The diagnosis, treatment and cause of a mechanical valve fracture are discussed.

Assessment of saphenous vein graft wall characteristics with intravascular ultrasound imaging

The wall characteristics of saphenous vein grafts (SVGs) after coronary artery bypass grafting (CABG) were assessed with intravascular ultrasound (IVUS) imaging. Twenty-seven SVGs in 25 patients who had undergone CABG were studied with IVUS in vivo. Ten SVGs excised from 6 patients who had undergone reoperation were studied with IVUS in vitro. The results were compared with the histopathologic findings. IVUS images of four SVGs studied within 1 month after CABG showed a thin and single-layer structure, which was almost identical to the IVUS features of a normal, fresh SVG. In five SVGs studied between 3 months and 1 year after CABG, the wall thickness was increased, and there were hypoechoic areas. In sixteen SVGs studied more than 2 years after CABG, two patterns were noted on IVUS imaging. One pattern was a triple-layer structure of alternating hyperechoic, hypoechoic, and hyperechoic bands seen in the angiographically normal sections of the SVGs. The second pattern was a heterogeneous, echogenic monolayer found in the angiographically irregular and diseased sections of the SVGs. Comparison of the in vitro IVUS images with the histopathology of the SVGs showed a strong correlation between the triple-layer structure and fibrointimal proliferation, and between the heterogeneous monolayer and atherosclerosis. In conclusion, IVUS is useful for assessing SVGs and for long-term qualitative monitoring of vein graft disease after CABG.

Reoperative coronary artery bypass via left thoracotomy

The patient was a 49-year-old woman. When she was 39 years old, she underwent coronary artery bypass grafting (left internal thoracic artery to left anterior descending artery, saphenous vein graft to first diagonal branch). At the age 48, she had effort angina. On coronary angiography, triple-vessel disease was found, and she was treated conservatively. Progression of the disease was confirmed with detection of the left circumflex artery associated with jeopardized collateral to the right coronary artery showing total occlusion. The patient underwent reoperation. Since the left internal thoracic artery was patent despite occlusion of the saphenous vein graft, the approach of left thoracotomy was employed. Under cardiopulmonary bypass with ventricular fibrillation and left vent through left atrial appendage, the right radial artery was anastomosed to the left circumflex artery from the descending thoracic aorta, and the right gastroepiploic artery was anastomosed to the right coronary artery (4AV branch). Patency of the bypass was confirmed postoperatively. We consider this operative technique was especially useful for reoperation in cases of a patent internal thoracic artery in which left thoracotomy can be conducted safely.

Epicardial Electrical Isolation of the Right Atrial Appendage on the Beating Heart With an Infrared Coagulator

To determine the clinical efficacy of application of infrared energy to the beating heart as a means of creating electrical blocks, an original infrared coagulator (KIRC-119; Phomec Inc, Tokyo, Japan) was applied to the atrium of a patient with atrial fibrillation. A postoperative electrophysiologic study was performed to confirm its efficacy. The coagulator was applied epicardially to the beating heart concomitant with an on-pump beating heart coronary artery bypass graft procedure. Sinus rhythm was restored during the operation, and the electrophysiologic study revealed that a bidirectional block had been created on the right atrial appendage. The infrared coagulator may facilitate performance of the epicardial Maze procedure on the beating heart.

Two cases of surgical treatment of recrudescent Stanford type A dissection after early thrombogenic closure without intimal tear

We reported two cases of thrombosed, Stanford A type acute aortic dissection, initially without intimal tear, later operated upon because of recrudescence. They admitted to our hospital with the symptoms of aortic dissection. Early examination of computed tomography and angiography demonstrated thrombosed type A aortic dissection showing a normal aortic figure, although accompanied by pericardial effusion, that was drainaged. Under strict BP control, however, repeat CT examination revealed recrudescent dissection of ascending aorta, making dissecting aneurysms. Graft replacement of ascending aorta was performed, on the 55th and 153th day after admission, and they were discharged.

Operations for Descending Thoracic Aortic Aneurysms Utilizing the Antithrombotic Cardiopulmonary Bypass.

1993年9月より1996年4月までに胸部下行大動脈を主体とした動脈瘤15例に対し, 左開胸による抗血栓処理部分体外循環法を用いた手術を行った. 疾患内訳は, 真性動脈瘤 (うち, 破裂例2例) 10例, 慢性解離性大動脈瘤4例, 大動脈縮窄症を伴う大動脈瘤1例で, 実施した手術は人工血管置換術12例. パッチ閉鎖術3例であった. 手術死亡は1例で, 虚血性心疾患を有する真性下行大動脈瘤破裂, ショックにて緊急手術を行い, 術後, 心筋梗塞によると考えられる急性心不全で失った. その他の14症例では本補助手段に起因すると考えられる血栓塞栓症等の合併症や術後諸臓器不全, 出血性合併症もなく, 全例軽快退院した. 今回の臨床的検討により, 本法は, 胸部下行大動脈手術の補助手段として, 安全で有効な方法であると考えられた.