Takayuki Kumamoto

Effects of coronary artery bypass grafting using internal mammary arteries for diabetic patients

OBJECTIVES In our institute, internal mammary arteries (IMAs) have been preferred for coronary artery bypass grafting (CABG) in diabetic patients. The purpose of this study was to evaluate the influence of diabetes and IMA grafting on survival after CABG. BACKGROUND The influence of diabetes on the results of CABG is not well documented, and there is controversy about whether the use of IMAs conveys greater survival benefits to diabetic patients. METHODS A total of 420 consecutive patients who underwent CABG from April 1990 to July 1998 were reviewed; 211 of these patients had diabetes mellitus at the time of surgery. Internal mammary artery grafts have been used with increasing frequency, and bilateral IMAs have been used when possible since 1993. Internal mammary artery grafts were used in 164 nondiabetic patients (78%) and in 155 diabetic patients (73%). Seventy-eight nondiabetic patients and 74 diabetic patients received bilateral IMA grafts. RESULTS The postoperative mortality was 2.4% in the nondiabetic and 2.8% in the diabetic group. With regard to postoperative complications, diabetic patients had a significantly higher rate of chest wound infection (p < 0.05), irrespective of whether IMAs were used or not. The use of bilateral IMAs did not increase the risk of chest wound infection in nondiabetic or diabetic patients. Overall survival curve, cardiac death-free curve and cardiac event-free curve were not affected adversely by diabetes, and in diabetic patients, CABG with saphenous veins alone conveyed significantly (p < 0.01) less long-term benefit than did CABG with at least one IMA graft. CONCLUSIONS It was suggested that IMA grafts should be preferred in diabetic patients.

Stroke after coronary artery bypass grafting in patients with cerebrovascular disease

BACKGROUND Stroke has been associated with a significantly increased mortality from coronary artery bypass grafting (CABG). To determine the predictors of stroke in patients undergoing CABG, we collected data on 472 consecutive patients. METHODS From March 1991 to March 1999, all patients undergoing CABG at our institution underwent routine duplex scanning of the extracranial carotid and vertebral arteries. Seven patients with symptomatic carotid stenosis were treated by carotid endarterectomy (CEA) before CABG. RESULTS There was a 10-fold increase in mortality (12.5%) associated with postoperative stroke. Many variables were analyzed by a multivariate technique and the severity of extracranial carotid artery stenosis was determined to be the only independent predictor of postoperative stroke (p < 0.01). None of the patients with carotid artery occlusion and none of the patients who underwent CEA before CABG experienced a stroke. CONCLUSIONS To reduce the stroke rate, the indications for prophylactic CEA may be extended for asymptomatic patients with carotid artery stenosis greater than 75%.

Aortic arch repair using hypothermic circulatory arrest technique associated with pharmacological brain protection

OBJECTIVE Hypothermic circulatory arrest is a standard procedure for the treatment of aortic arch. However, there is a time limit for this procedure. There is now an urgent need to develop prophylactic measures to extend the time limit. We have used a pharmacological mixture of thiopental, nicardipine and mannitol for all patients undergoing circulatory arrest since 1991 to extend the safe limit. The purpose of this study was to analyze the neurological complications demonstrated by these patients and to evaluate the brain-protective effects of our measure. METHODS The clinical records of 75 consecutive patients undergoing an aortic arch repair using a hypothermic circulatory arrest technique during the past 8 years were retrospectively reviewed. Systemic cooling was continued until a total disappearance of EEG activity. Prior to circulatory arrest, 15 or 30 mg/kg of thiopental, 20 mg of nicardipine and 300 ml of mannitol were infused into the venous reservoir of a cardiopulmonary bypass circuit. Graft replacement was performed in all patients and the extent of replacement was a total aortic arch in 43 patients, a distal aortic arch in 17, a hemiarch in 13 and a distal aortic arch and a total descending aorta in two. RESULTS The duration of circulatory arrest ranged from 16 to 80 min (mean 41.5 min), and it exceeded 45 min in 37 patients. Operative mortality was 10.7% and two patients died of stroke. Three patients had permanent and three other patients had transient neural deficits. The incidence of stroke was 8.0% as a whole, and no correlation between the incidence of neurological complications and the duration of circulatory arrest was found. A multivariate analysis showed that the duration of circulatory arrest was determined as a predictor of neither operative mortality nor postoperative stroke. CONCLUSIONS The findings of the present study suggest that our pharmacological brain protection appears to be effective for safely extending hypothermic circulatory arrest.

Coronary-coronary bypass using the internal thoracic artery: a sparing procedure of the arterial conduit.

Abstract  Background: The internal thoracic artery (ITA) is well known to be the best conduit for coronary artery bypass grafting. However, the bilateral use of ITAs remains limited because in situ right ITAs (RITAs) do not possess an adequate length to be directed to the posterolateral myocardium. We thus considered using free ITAs for conduits between the two segments of the same coronary artery. Methods: From March 1997 to May 1999,17 patients underwent coronary‐coronary bypass grafting (C‐CBG) using free ITAs. Early operative results were analyzed. C‐CBG was indicated when the right ITA had an inadequate length or when a distal part of the ITA was left unused. Results: No patient died after C‐CBG and none have experienced angina since C‐CBG (mean follow‐up period 27.3 ± 19.8 months). Postoperative angiography was performed in all subjects at discharge. Only one coronary‐coronary bypass graft was occluded, the other grafts were patent, and there were no stenotic changes. Bilateral ITAs were used in 75% of the patients undergoing CABG during the period of this study. Conclusions: C‐CBG can expand the use of bilateral ITAs and can provide an alternative method for revascularization of the posterolateral myocardium.

Right ventricular myxoma in a 71-year-old female

Right ventricular myxoma in elderly is very rare and this is the 36th case report of right ventricular myxoma in Japan. A healthy 71-year-old female with no symptoms or constitutional signs except heart murmur was hospitalized. Findings of transthoracic echocardiogram, CT scan, MRI and angiocardiogram demonstrated a mobile tumor in the right ventricular outflow tract. Transesophageal echocardiogram clearly revealed that the stalk was arising from the right ventricular free wall. Under cardiac arrest, right atriotomy was made and a gelatinous tumor (4.5 x 2 x 2 cm in size, 7.3 g in weight) was excised with 5 mm of surrounding endocardium and a few millimeters of underlying myocardium through the tricuspid valve. Histopathologically, the tumor was diagnosed as a myxoma. Her postoperative course was uneventful.

Aortic valve replacement in a patient with idiopathic thrombocytopenic purpura

A patient with aortic regurgitation and idiopathic thrombocytopenic purpura underwent a successful valve replacement. Cardiac surgery requiring a cardiopulmonary bypass in idiopathic thrombocytopenic purpura can be safely carried out with the preoperative intravenous administration of high-dose gammaglobulin, which may thereby reduce the need for either perioperative transfusion or prophylactic splenectomy.

Posterior ventricular septal perforation in an 80-year-old man

Ventricular septal perforation is a complication of acute myocardial infarction that is fatal unless treated surgically. Posterior ventricular septal perforation remains particularly difficult to repair successfully. We report an 80-year-old man with postinfarction posterior ventricular septal perforation who successfully underwent surgical repair using a technique similar to that described by Daggett et al. and was discharged in good health without postoperative septal shunt.

Coronary-Coronary Bypass Using the Internal Thoracic Artery: A Sparing Procedure of the Arterial Conduit

Abstract Background: The internal thoracic artery (ITA) is well known to be the best conduit for coronary artery bypass grafting. However, the bilateral use of IT As remains limited because in situ right IT As (RITAs) do not possess an adequate length to be directed to the posterolateral myocardium. We thus considered using free ITAs for conduits between the two segments of the same coronary artery. Methods: From March 1997 to May 1999, 17 patients underwent coronary‐coronary bypass grafting (C‐CBG) using free ITAs. Early operative results were analyzed. C‐CBG was indicated when the right ITA had an inadequate length or when a distal part of the ITA was left unused. Results: No patient died after C‐CBG and none have experienced angina since C‐CBG (mean follow‐up period 27.3 ± 19.8 months). Postoperative angiography was performed in all subjects at discharge. Only one coronary‐coronary bypass graft was occluded, the other grafts were patent, and there were no stenotic changes. Bilateral ITAs were used in 75% of the patients undergoing CABG during the period of this study. Conclusions: C‐CBG can expand the use of bilateral ITAs and can provide an alternative method for revascularization of the posterolateral myocardium.