Diabetes Mellitus Induces Hyperreactivity of 5-Hydroxytryptamine (5-HT)-Induced Constriction in Human Internal Thoracic Artery and Is Associated with Increase in the Membrane Protein Level of 5-HT2A Receptor.

Studies indicate that 5-hydroxytryptamine (5-HT) released from activated platelets in coronary artery bypass grafting (CABG) induces 5-HT2A receptor-mediated graft spasm. We previously reported that 5-HT-induced constriction of human endothelium-denuded saphenous vein (SV) was significantly augmented in patients with diabetes mellitus (DM) than in patients without DM (non-DM), without changes in the levels of the membrane-bound 5-HT2A receptor of their smooth muscle cells. Although the internal thoracic artery (ITA) is the key graft conduit for CABG, the effect of DM on the ITA graft spasm is still unclear. Therefore, in this study, we investigated the effect of DM on 5-HT-induced vasoconstriction and the level of membrane-bound 5-HT2A receptor in ITA grafts. 5-HT-induced constriction of the isolated human endothelial-denuded ITA was significantly higher in patients with DM than in patients without DM. In addition, the level of the 5-HT2A receptor in the membrane fraction of human ITA smooth muscle cells was significantly higher in patients with DM than in those without DM. These results demonstrate that DM is a risk factor for CABG in both venous and arterial conduits, and that it differentially affects the level of the membrane-bound 5-HT2A receptor in the venous and arterial smooth muscle cells.

Angiotensin II, as well as 5-hydroxytriptamine, is a potent vasospasm inducer of saphenous vein graft for coronary artery bypass grafting in patients with diabetes mellitus.

Diabetes mellitus (DM) is an important risk factor for adverse outcomes of coronary artery bypass grafting. The bypass grafts harvested from patients with DM tend to go into spasm after their implantation into the coronary circulation. To clarify the contribution of 5-hydroxytriptamine (5-HT) and angiotensin II (AngII) in the bypass graft spasm, we examined the contractile reactivity to 5-HT or AngII of isolated human endothelium-denuded saphenous vein (SV) harvested from DM and non-DM patients. The 5-HT-induced constriction of the SV was significantly augmented in the DM group than in the non-DM group, which is similar to our previous report. AngII-induced constriction of the SV was also significantly augmented in the DM group than the non-DM group. Especially in the non-DM group, the AngII-induced maximal vasoconstriction was markedly lower than the 5-HT-induced one. Meanwhile, the increasing rates of AngII-induced vasoconstriction in the DM group to the non-DM group were significantly greater than those of 5-HT-induced vasoconstriction. These results indicate that 5-HT is a potent inducer of SV graft spasm in both DM and non-DM patients, while AngII is a potent inducer of SV graft spasm only in patients with DM. Furthermore, the protein level of AngII AT1 receptor (AT1R), but not the protein level of 5-HT2A receptor, in the membrane fraction of the SV smooth muscle cells of DM patients was significantly increased as compared with that of the non-DM patients. These results suggest that the mechanism for hyperreactivity to AngII in the SV from DM patients is due to, at least in part, the increase in the amount of AT1R on membrane of the SV smooth muscle cells.

[Valve plasty for mitral regurgitation caused by partial papillary muscle rupture after acute myocardial infarction;report of a case].

A 58-year-old woman was referred to our hospital because of acute myocardial infarction. Percutaneous coronary intervention for total occlusion of the circumflex coronary artery was performed successfully. However, she had heart failure that was gradually getting worse because of mitral valve regurgitation. Therefore, we performed valve plasty using the resection and suture method for mitral regurgitation caused by partial papillary muscle rupture. Her postoperative course was uneventful, and she was discharged on postoperative day 26. At 6 months after the operation, her functional status was New York Heart Association(NYHA) class I and transthoracic echocardiogram showed no mitral regurgitation( MR).

Mitral valve replacement and septal myectomy for hypertrophic obstructive cardiomyopathy.

A 76-year-old woman with a diagnosis of hypertrophic obstructive cardiomyopathy was referred to our hospital's surgical department. Her echocardiogram revealed diffuse left ventricular hypertrophy, moderate mitral valve regurgitation with systolic anterior motion of the mitral valve, and left ventricular obstruction with a peak outflow gradient of 108 mm Hg. We performed a transaortic rectangular septal myectomy with an incision at a width, depth, and length of 1 cm, 1 cm, and 3 cm, respectively. However, the transesophageal echocardiogram revealed residual left ventricular obstruction and systolic anterior motion, and we subsequently replaced the mitral valve with a mechanical valve. The patient's postoperative course was uneventful, and the peak outflow gradient decreased to 15 mm Hg. Although transaortic septal myectomy is the most common surgery currently used for hypertrophic obstructive cardiomyopathy, mitral valve replacement should remain an option in patients with diffuse left ventricular hypertrophy who fail to improve after myectomy alone.

Recurrent upper limb ischaemia due to a crutch-induced brachial artery aneurysm.

An 83-year old man who had used bilateral axillary crutches for 67 years was referred to our hospital for acute left upper limb ischaemia. He underwent successful recanalization through emergent catheter thromboembolectomy. However, a crutch-induced left brachial artery aneurysm was subsequently detected by computed tomography. Therefore, we performed aneurysm exclusion and subsequent saphenous vein bypass grafting. When a crutch user presents with upper limb ischaemia, a high index of suspicion and early identification of the crutch induced vascular injury are mandatory for appropriate treatment.

Posterior leaflet extension with a patch of bovine pericardium for type IIIb mitral regurgitation.

A 36-year-old man was referred to our hospital because of heart failure, and severe mitral regurgitation due to restriction of the posterior mitral leaflet was detected by an echocardiogram. We performed posterior leaflet extension with a patch of bovine pericardium. The postoperative course was uneventful, and the patient was discharged on postoperative day 23. Posterior leaflet extension is useful for mitral regurgitation due to posterior leaflet restriction.

Mycotic pseudoaneurysm of the ascending aorta caused by Escherichia coli.

An 81-year old woman with high fever and a history of hospital admission because of pyelonephritis 3 months previously was transferred to our hospital. Contrast-enhanced computed tomography revealed a mycotic pseudoaneurysm in the ascending aorta and a massive pericardial effusion. We resected the ascending aorta and the proximal part of the brachiocephalic artery and performed in situ revascularization with a prosthetic vascular graft. Bacterial examination proved that the causative micro-organism was Escherichia coli. The prosthetic graft was wrapped with a pedicled omentum following completion of the aortic reconstruction. Her postoperative course was uneventful. She was discharged from the hospital 1 month postoperatively.

[Combined valve surgery in end-stage renal disease patient with porcelain aorta and mitral annulus calcification].

A 66-year-old woman, who had been receiving regular hemodialysis for 11 years, was referred to our hospital because of heart failure due to combined valve disease complicated by porcelain aorta and mitral annulus calcification. We performed ascending aortic replacement under hypothermic arrest, and double valve replacement and tricuspid valve annuloplasty during rewarming. It was noted that the annulus of P3 of mitral valve had been replaced with atherosclerotic plaque containing calcification. We did not perform débridement. We placed non-everted horizontal mattress sutures from the left ventricle to the atrium on the anterior annulus and P1 to P2 annulus, and everted horizontal mattress sutures on the left atrial wall close to the calcified P3 annulus. Then, we successfully replaced the mitral valve with a 23-mm St. Jude Medical valve in a supra-annular position. The patient was discharged from the hospital 44 days after the operation.

Transtricuspid approach in redo surgery for post-infarction ventricular septal rupture.

A 59-year-old man, who had been treated using the infarction exclusion technique for inferior post-infarction ventricular septal rupture (VSR) 4 months previously, was readmitted because of deterioration of mitral valve regurgitation, residual shunt, and progression of pulmonary hypertension. We performed mitral valve replacement via the transseptal approach, patch closure of the defect via the transtricuspid approach, and tricuspid valve annuloplasty. The post-operative course was uneventful. The transtricuspid approach is useful in redo surgery for post-infarction VSR.

Emergent coronary artery bypass grafting after a broken Rotablator drive-shaft.

A 75-year-old man, who presented with acute myocardial infarction and cardiogenic shock underwent emergency cardiac catheterization, assisted by catecholamine administration, respiratory support with intubation and intra-aortic balloon pumping (IABP). The coronary arteriogram showed a high-grade obstruction of two main branches of the left coronary artery. The occlusion of the left anterior descending coronary artery required immediate treatment. As it was heavily calcified, the cardiologists were forced to use Rotablator®, but the device became stuck and the drive-shaft broke. An emergency coronary artery bypass grafting (CABG) with left internal thoracic artery and saphenous vein graft and mitral valve annuloplasty was performed successfully. The patient was weaned off IABP on the fourth postoperative day, and a defibrillator was implanted on the 81st postoperative day because of heart failure. After these procedures, his general state improved gradually and he was able to leave the hospital, walking alone on the 101st postoperative day. Various reports have appeared describing residual foreign bodies in coronary arteries, and almost 90% of these cases can be dealt with by intravascular procedures, but some need removal by open-chest surgery. An early decision by the cardiologists to go to surgery is recommended to save lives. There has been no previous report of emergent CABG after a stuck Rotablator® tip due to a 'broken drive-shaft'. However, because damage is possible even with reliable devices, there should be no hesitation converting to open-heart surgery in such cases.

Clinical outcome of aortic valve replacement with 16-mm ATS-advanced performance valve for small aortic annulus.

BACKGROUND: Various surgical techniques have been proposed to treat small aortic annulus. We have used small-diameter mechanical valves for small aortic annulus. The present study examined aortic valve replacement with small diameter mechanical valves to determine their effectiveness. METHODS: The study included 67 patients who underwent elective, isolated aortic valve replacement with ATS-Advanced Performance (AP) valves (ATS Medical, Inc, Minneapolis, MN) within our department. The patients were divided into two groups; patients receiving the 16-mm AP valve (16-mm group) and those receiving valves 18-mm AP or larger (>16-mm group). RESULTS: The mean age of the 16-mm group was significantly higher than that of the >16-mm group. Body surface area was significantly smaller in the 16-mm group than the >16-mm group. We found no significant differences in preoperative conditions between the groups. The effective orifice area index of the mechanical valve was lower in the 16-mm group (0.87+/-0.06 vs 1.12+/-0.13 cm2/m2, p<0.0001). Six patients (40%) in the 16-mm group fell into the category of prosthesis-patient mismatch cases. Although the postoperative pressure gradient was higher in the 16-mm group (33.7+/-12.5 vs 23.16+/-8.78, p<0.01), left ventricular mass index and left ventricular ejection fraction at early and at late follow-up improved from the preoperative period in both groups. We found no significant differences in incidence of postoperative complications, including death. CONCLUSIONS: We believe aortic valve replacement with small-diameter mechanical valves (the ATS-AP valves) in patients with a small annulus provides satisfactory remote prognosis. The use of mechanical valves in elderly patients is considered acceptable with strict clinical monitoring to prevent thromboembolism and anticoagulation therapy-induced complications.

Reinforcement of saphenous vein graft with ePTFE graft for axillocoronary bypass grafting.

Arteriosclerosis in the ascending aorta is widely accepted as a strong risk factor for the occurrence of stroke after coronary artery bypass grafting (CABG). The aortic no-touch technique, with a variety of modifications, has been used to reduce the risk of post-CABG stroke. Saphenous vein grafts (SVGs) have been used for axillocoronary bypass grafting, a modification of the aortic no-touch technique. However, kinking or compression often occurs with SVGs. We report here the successful application of an 8-mm expanded polytetrafluoroethylene graft, of the external bead support type, that was used to cover an SVG during axillocoronary bypass grafting.

Mycotic pseudoaneurysm of the brachiocephalic artery.

A 73-year-old woman with a history of hypertension and hyperlipidemia presented with a sharp pain ranging from the right shoulder to the upper limb. She had suffered a sharp pain at rest accompanied by general fatigue and nausea for about ten months prior to admission. Her white blood cell count was 12,800/microl, and her serum C-reactive protein was 17.5 mg/dl. A chest computed tomography scan revealed an aneurysmal change of the origin of the brachiocephalic artery. Pseudoaneurysm due to infection and aortic dissection was considered as a preoperative diagnosis. A total arch replacement was performed under cardiopulmonary bypass, deep hypothermia, and selective cerebral perfusion. Postoperatively, a bacteriologic culture of the contents of the aneurysm revealed Staphylococcus aureus. Perioperative administration of antibiotics was effective and the postoperative course was uneventful.