Kimihiro Yoshimoto

Reoperations after failure of stent grafting for type B aortic dissection: report of two cases.

We describe our successful management of two patients who suffered complications after stent grafting for Type B aortic dissections. One patient was found to have stent-graft migration, which we treated with repeat aortic stent grafting, and the other patient had a proximal endoleak and total occlusion of the stent graft, which we treated with open surgical repair. We discuss the measures used to assist us in deciding on the most appropriate surgery, as well as the treatment alternatives.

Histamine H1-receptor-mediated increase in the Ca2+ transient without a change in the Ca2+ current in electrically stimulated guinea-pig atrial myocytes.

The effects of histamine on the intracellular Ca2+ concentration ([Ca2+]i), action potential and membrane currents were assessed in single atrial myocytes prepared from guinea‐pigs. Histamine caused a concentration‐dependent increase in the [Ca2+]i transient in indo1/AM loaded myocytes when stimulated electrically at 0.5 Hz. However, the maximum increase in [Ca2+]i transient produced by histamine was less than 50% of that elicited by isoprenaline. The histamine‐induced increase in [Ca2+]i transient was significantly inhibited by chlorpheniramine, but not by cimetidine. Pretreatment with nifedipine nearly completely suppressed the histamine‐induced increase in [Ca2+]i transient. Cyclopiazonic acid did not affect the histamine response. In the whole‐cell current‐clamp mode of the patch‐clamp method, both histamine and isoprenaline prolonged action potential duration (APD) in atrial myocytes. In the presence of Co2+ or nifedipine, the isoprenaline‐induced APD prolongation was abolished and an APD shortening effect was manifested, while histamine still increased APD. The APD prolongation elicited by histamine was reversed by chlorpheniramine. In the voltage‐clamp mode, the histamine‐sensitive membrane current was inwardly rectifying and reversed close to the calculated value of the K+ equilibrium potential. Histamine had no apparent effect on L‐type Ca2+ current, in contrast to the pronounced effect of isoprenaline. These results indicate that in guinea‐pig atrial myocytes stimulation of H1‐receptors with histamine does not directly activate Ca2+ channels but causes an elevation of [Ca2+]i transient by increasing Ca2+ influx through the channels during the prolonged repolarization of action potentials resulting from inhibition of the outward K+ current.

Involvement of tyrosine phosphorylation in the positive inotropic effect produced by H1-receptors with histamine in guinea-pig left atrium

We investigated the effect of stimulation of H1‐receptors with histamine on protein tyrosine phosphorylation levels in guinea‐pig left atrium and evaluated the influences of tyrosine kinase inhibitors on the positive inotropic effect mediated by H1‐receptors in this tissue. Histamine induced an increase in tyrosine phosphorylation in four main clusters of proteins with apparent molecular weights of 25, 35, 65 and 150 kDa. Tyrosine phosphorylation of these proteins attained a peak around 2–3 min following histamine stimulation and then declined to or below basal levels. Histamine‐induced protein tyrosine phosphorylation was antagonized by the H1‐receptor antagonists mepyramine (1 μM) and chlorpheniramine (1 μM), but not by the H2‐receptor antagonist cimetidine (10 μM). The positive inotropic effect of histamine was depressed in a concentration‐dependent manner by the tyrosine kinase inhibitors tyrphostin A25 (50 to 100 μM) and genistein (10 to 50 μM) but not by the inactive genistein analogue daidzein (50 μM). The positive inotropic effect of isoprenaline was unchanged by tyrphostin A25 and genistein. At a concentration of 1 μM histamine produced a dual‐component positive inotropic response composed of an initial increasing phase and a second and late developing, greater positive inotropic phase. Treatment with tyrphostin A25 (100 μM) and genistein (50 μM), but not daidzein (50 μM), significantly attenuated the two components of the inotropic response, although genistein suppressed the initial component more markedly than the late component. We conclude that increased protein tyrosine phosphorylation may play an important role in initiating at least some part of the positive inotropic effect of H1‐receptor stimulation in guinea‐pig left atrium.

Application of the reversed elephant trunk technique during total thoracoabdominal replacement in patients with Marfan's syndrome

Abstract The reversed elephant trunk operation has been applied in patients with extensive aortic involvement as a scheduled staged operation. We report application of the same technique in two patients with Marfans syndrome. The two patients underwent total replacement of the thoracoabdominal aorta for a DeBakey IIIb aortic dissection. The proximal end of the prosthetic graft was invaginated to facilitate future proximal operation. No complication related to the trunk had been observed during the follow‐up period. (J Card Surg 1998; 13:56–59)

Abdominal Compartment Syndrome Causing Respiratory Failure During Surgery for a Ruptured Descending Thoracic Aneurysm: Report of a Case

Elevated intra-abdominal pressure causing widespread organ dysfunction is known as abdominal compartment syndrome (ACS). The subject of our case report is a 64-year-old man who underwent repair of a ruptured descending thoracic aortic aneurysm (TAA) under deep hypothermic circulatory arrest. During the operation, decompression laparotomy was required to relieve intra-abdominal hypertension causing respiratory failure, before the patient could be weaned off cardiopulmonary bypass. We report this case to alert surgeons to the fact that ACS can occur during surgery on the thoracic aorta, especially if massive fluid resuscitation is required and venous drainage for extracorporeal circulation is less than optimal. Early recognition and prompt decompression by laparotomy is essential to save the life of the patient.

Surgical Treatment for a Coronary Artery Saccular Aneurysm Located in the Left Main Trunk

冠動脈壁の高度石灰化を伴う左冠動脈主幹部に起始する冠動脈嚢状瘤の手術を経験したので報告する.症例 は 67歳男性,糖尿病性腎症により 12年間の透析歴がある.心不全に対し当院循環器内科にて加療および心 精査が行われた.冠動脈造影にて左冠動脈主幹部+二枝病変および左冠動脈主幹部の冠動脈嚢状瘤を認め当 科紹介となった.治療として冠動脈バイパス術(二枝)および冠動脈瘤切除+冠動脈形成術を予定した.心 嚢内に強固な癒着を認め剝離ののち,体外循環補助心停止下に肺動脈本幹を離断し瘤に到達し切開,瘤内に 位置する冠動脈主幹部壁に穿孔を認めた.大伏在静脈でのパッチを用いて孔を閉鎖しさらに瘤壁で被い,併 わせて冠動脈バイパス術を行った.摘出した瘤壁の病理検査では冠動脈解離の所見を認めた.術後の冠動脈 造影では冠動脈瘤は消失,順行性の血流が保たれ,グラフトの開存が確認された.日心外会誌 47巻 4号: 178-182(2018) キーワード:冠動脈嚢状瘤;左冠動脈主幹部;パッチ形成術;動脈硬化;冠動脈解離