Naoko Nagano

Coronary Artery Bypass Grafting Using the Radial Artery: Midterm Results in a Japanese Institute

BACKGROUND To avoid remote cardiac events associated with graft occlusions, arterial conduits are being increasingly utilized in coronary artery bypass grafting (CABG). The development of antispasmic agents has enabled the use of the radial artery as a graft conduit in CABG. METHODS Between December 1995 and December 1998, 920 consecutive isolated CABG operations were performed at Shin-Tokyo Hospital. The radial artery was used for graft conduits in 475 of these patients, and their data were analyzed in this study. The patients were followed to determine midterm graft patency, cardiac events, and survival. All data are given as mean +/- standard deviation. The end points were patient death or occurrence of cardiac events. RESULTS The radial artery was used in 475 patients (366 males and 109 females, with a mean age of 64.5+/-8.5 years). The left internal mammary artery was used in 94.9% of patients, the right internal mammary artery in 17.5%, the gastroepiploic artery in 50.9%, the inferior epigastric artery in 0.2%, and the saphenous vein in 39.2%. The in-hospital morbidity and mortality rates of the studied group were 12.8% and 0.6%, respectively. A major complication related to radial artery harvesting, compartment syndrome of the arm due to postoperative bleeding, was observed in 1 patient. No postoperative myocardial infarction attributable to radial artery bypass was observed. During the late follow-up period of 3.5+/-0.9 years, cardiac events were observed in 63 patients, giving actuarial 2- and 3-year event-free rates of 92.8% and 89.6%, respectively. A total of 24 late deaths were noted, including seven cardiac deaths, giving actuarial 2- and 3-year survival rates of 98.1% and 97.2%, respectively. Postoperative angiography was performed in selected patients. The cumulative graft patency rate of the radial artery was 93.0% during the mean angiographical follow-up period of 1.5+/-1.1 years. CONCLUSIONS No adverse effects were noted after CABG using a radial artery graft in this short- and midterm follow-up period.

Coronary artery bypass grafting for patients with non-dialysis-dependent renal dysfunction (serum creatinine ≧2.0 mg/dl)

INTRODUCTION Patients with renal dysfunction carry a risk of coronary atherosclerosis. The purpose of this study was to evaluate the outcome after coronary artery bypass grafting (CABG) in patients with decreased renal function (serum creatinine > or =2.0 mg/dl). METHODS We retrospectively analyzed consecutive patients who had undergone isolated CABG at Shin-Tokyo Hospital between May 1, 1991 and April 31, 2000. Preoperative, perioperative, and follow-up data of the non-dialysis-dependent patients with preoperative serum creatinine equal to or more than 2.0mg/dl (group R, n=59) were collected, and compared with those of the control patients (serum creatinine < 2.0, group C, n=1666). Group R was further divided into the off-pump and on-pump CABG group and their perioperative results were compared. RESULTS Group R included 51 males and eight females with a mean age of 66.4. The mean number of anastomoses was not significantly different between groups; however, clump time and pump time were longer in group R. Postoperative recovery was longer in group R than in group C, which is associated with a more frequent occurrence of major complications (28.8% in group R and 10.7% in group C, P<0.0001) and mortalities (6.8% in group R and 0.5% in group C, P<0.0005). The patients who underwent off-pump CABG experienced relatively faster recovery than those who underwent on-pump CABG, despite decreased renal function. At the mean follow-up of 2.4 years, the actuarial 3-year survival rate of groups R and C were 75.3 and 96.9%, respectively (P<0.0001), excluding hospital mortality. The actuarial 3-year cardiac event-free rate was 76.7% in group R and 87.3% in group C (P<0.05). CONCLUSIONS Patients with decreased renal function carry significant operative risks and require prolonged hospital care. Even after adequate surgical revascularization was completed, the long-term cardiac event-free and survival rates in the patients with renal dysfunction were inferior to the patients with normal renal function.

Off-Pump Coronary Artery Bypass Mid-Term Results

OBJECTIVES Off-pump coronary artery bypass grafting (CABG) on the beating heart has become popular procedure in cardiac surgery and its initial results appeared favorable. We report our early and mid-term results of off-pump CABG performed at Shin-Tokyo Hospital. METHODS Medical records of patients undergoing off-pump or conventional on-pump CABG from September 1, 1996, to August 31, 1999 were retrospectively reviewed. Patients underwent off-pump CABG were further classified into 2 groups; MIDCAB (Off-pump CABG for single vessel revascularization via a small skin incision) and OPCAB (off-pump CABG mainly approached via midline sternotomy) group. Their preoperative, perioperative, and follow-up data were collected and analyzed. RESULTS Among a total of 995 cases of CABG, 194 cases were off-pump CABG (male/female 142/52, mean age 66.9). The mean number of distal anastomoses in off-pump CABG was 1.9 +/- 0.9 (1.0 +/- 0.0 in MIDCAB and 2.3 +/- 0.7 in OPCAB), which was significantly fewer than in on-pump CABG (3.6 +/- 1.1), with p < 0.0001. Intubation time (5.3 +/- 5.7 hours in off-pump CABG vs 13.1 +/- 24.2 hours in on-pump CABG), ICU stay (1.7 +/- 1.1 vs 3.2 +/- 3.0 days), and postoperative hospital stay (14.0 +/- 7.9 vs 18.1 +/- 12.1 days) in off-pump CABG were significantly shorter than in on-pump CABG (p < 0.0001). In the off-pump CABG group, there were no in-hospital deaths and 14 major complications, fewer than in on-pump CABG (8 hospital deaths and 114 major complications). Postoperative angiography before hospital discharge was conducted in 80 patients (41.2%) and showed 2 occlusions, giving a graft patency rate of 98.6% in the off-pump group. During follow-up (0.9 +/- 0.6 year) period, there were 5 non-cardiac deaths and 20 cardiac events in the off-pump group. The actuarial survival rate at 36 months was 94.6% for off-pump CABG, showing no significant difference from the rate for conventional CABG patients (95.2% at 36 month, p = NS) The event-free rate was 84.0% at 36 months in off-pump CABG patients; however, which was less favorable than on-pump CABG patients (88.0% at 36 months, p < 0.05). CONCLUSIONS Both in-hospital and mid-term results for off-pump CABG patients were acceptable. Isolated CABG can thus be safely performed without cardiopulmonary bypass. Advances in coronary stabilization have contributed to these improved results. The observed long-term cardiac events may be related to incomplete revascularization.

Gender Differences in the Clinical Characteristics Among Japanese Patients With Obstructive Sleep Apnea Syndrome

BACKGROUND Gender differences in the prevalence of various manifestations of obstructive sleep apnea syndrome (OSAS) is not as great as previously believed. The aim of the present study was to clarify the clinical patient characteristics of Japanese women and men with OSAS. METHODS A cross-sectional case-match control study was performed on patients from two sleep disorder centers. Two hundred forty-five women with OSAS were classified into premenopausal (n = 70) and postmenopausal (n = 175) groups. As well, 245 men matched for both age and apnea-hypopnea index (AHI) and another 245 men matched for age and body mass index (BMI) were established. We compared descriptive variables between genders in both the premenopausal and the postmenopausal female patient groups. RESULTS As a whole, female patients had significantly higher BMI than AHI-matched male patients (p < 0.05) and a significantly lower value of AHI than BMI-matched male patients (p < 0.001). Female patients had lower Epworth Sleepiness Scale scores than BMI-matched male patients (p < 0.05). On logistic regression analysis, presence of hypertension was significantly associated with BMI (>or=25 kg/m(2)), AHI (>or= 15 to < 30 events/h; >or= 30 to < 60 events/h; >or= 60 events/h), and presence of both hyperlipidemia and diabetes mellitus. However, gender differences were not associated with the occurrence of hypertension. Female patients had significantly lower optimal levels of continuous positive airway pressure than male patients. CONCLUSIONS Our results suggest that both the OSAS severity and the strength of pharyngeal closure is less in Japanese female patients than in male patients. Moreover, Japanese female patients are thought to have less daytime sleepiness than male patients but a similar rate of hypertension as male patients.

Surgical management of unstable patients in the evolving phase of acute myocardial infarction

BACKGROUND Acute myocardial infarction (AMI) can be treated with thrombolysis or coronary catheter intervention; surgical treatment--coronary artery bypass grafting (CABG)--is reserved for the patients in whom other procedures have failed. We performed CABG in 47 patients during the evolving phase of AMI, and analyzed their short-term and long-term results. METHODS Preoperative, intraoperative, and postoperative data were analyzed in patients who underwent emergency CABGs for AMI between January 1, 1992, and July 31, 1998. CABGs performed more than 7 days after AMI were excluded from this study. RESULTS The subjects were 47 patients (33 males and 14 females) with AMI who were treated by emergency CABG. Intraaortic balloon pumping was used in 44 cases and percutaneous circulatory pulmonary support was used in 3 cases. The mean interval between the onset of AMI and surgery was 27.4 +/- 27.9 hours. The mean number of bypass grafts was 3.0 +/- 1.1, and at least 1 arterial conduit was used in 45 cases (95.7%). Aortic clamp time, pump time, and operative time were 64.7 +/- 31.7, 117.3 +/- 55.2, and 313.2 +/- 84.8 minutes, respectively. IABP or percutaneous cardiopulmonary support were removed in the intensive care unit (ICU) 30.0 +/- 28.9 hours after CABG. The patients were extubated 41.4 +/- 40.5 hours after surgery, remained in ICU for 4.7 +/- 2.7 days, and were discharged from the hospital after 27.0 +/- 22.5 days. Three patients died from multiorgan failure related to postoperative sepsis, and 8 cases of major complications were observed. The actuarial 5-year survival rate of the patients treated with CABG was 83.0%. CONCLUSIONS Surgical treatment in the unstable patients after AMI can be performed with acceptable risk. Arterial revascularization may contribute to improvement in long-term results.

Infected aneurysm of the aortic arch with purulent pericarditis caused by Streptococcus pneumoniae

A 76-year-old woman had a chest pain and high fever, and was admitted to the intensive care unit diagnosed as acute pericarditis. Enhanced CT-scan showed a 47-mm aneurysm in the aortic arch which seemed to be impending rupture and the part of the aorta looked like a pseudoaneurysm. Emergent total aortic arch replacement with a rifampicin-bonded Dacron graft was performed. Pericardial effusion was purulent and the aorta was infected with pus discharge in the aortic wall. There were some ulcerations on the surface of the luminal wall of the aorta. One of them was penetrating into the pericardial space causing a pseudoaneurysm. Both pericardial effusion and excised aortic wall were sent to culture study and resulted in positive for Streptococcus pneumoniae. The infection of the aorta, with erosion into the pericardial space, seemed to be the cause of purulent pericarditis. Antibiotic therapy was commenced immediately after surgery and continued for four weeks. Though she had neurological deficit after surgery, her infection was well controlled and there was no recurrence of infection 11 months after surgery.

Coronary artery bypass grafting in patient with malignant neoplasm. Efficacy of coronary artery bypass grafting on beating heart.

OBJECTIVE Coronary artery bypass grafting (CABG) prior to noncardiac major surgery has effectively decreases short- and long-term mortality related to coronary ischemia. Coronary artery bypass on the beating heart is conducted to avoid the risk of cardiopulmonary bypass and it has contribute to shorten recovery time. METHODS Subjects were 19 patients with malignant neoplasm for whom a retrospective chart review was made between Jan. 1, 1992 and July 31, 1998. In the early phase of this study, between Jan. 1, 1992, and Dec. 31, 1997, CABG was performed using cardiopulmonary bypass, and late phase, between Jan. 1, 1998, and July 1, 1998, CABG was done on the beating heart without cardiopulmonary bypass. RESULTS Conventional CABG was performed in 12 patients with neoplasms (10 male and 2 female, age 64.7 +/- 6.1 years), and CABG on the beating heart was performed in 7 patients (6 male and 1 female, age 68.0 +/- 7.5 years). Fewer number of bypass grafts were made in the beating-heart CABG group (1.3 +/- 0.5 in beating-heart CABG versus 3.9 +/- 1.1 in conventional CABG). No cardiac events occurred in either group during the surgery for malignant tumors. The operative interval between CABG and cancer surgery was significantly shorter in the beating-heart CABG group (21.8 +/- 17.9 days in beating-heart CABG versus 53.5 +/- 42.9 days in conventional CABG, p < 0.05). CONCLUSION Patients with severe coronary artery disease and malignant neoplasms should undergo coronary artery revascularization before the neoplasm is treated. CABG on the beating-heart was safe and effective procedure in those with malignant neoplasms.

Risk analysis of urgent coronary artery bypass grafting

We analyzed the risk factors of morbidity and mortality associated with urgent coronary artery bypass grafting (CABG) for impending myocardial infarcton. Among 1,428 consecutive patients who underwent isolated on-pump CABG between 1992 and 1998, a total of 126 were urgent cases. Their inhospital and long-term data were analyzed by the Kaplan-Meier method or logistic model. The mean number of grafts performed during urgent CABG was 3.2, and arterial reconstruction was performed in 117 (93.9%) cases. Major postoperative complicatons occurred in 64 cases (50.8%), and there were 9 inhospital deaths (7.1%). Significant predictor of inhospital death, identified by multivariate analysis, was a history of cerebral vascular accident. During a mean follow-up period of 3.1 years, there was a total of 7 remote deaths giving an actuarial 5-year survival rate of 93.5% (excluding inhospital deaths). Remote cardiac events occurred in 23 patients, giving an actuarial 5-year event-free rate of 74.8%. Multivariate logistic regression analysis found that risk factors influencing cardiac events were poor left ventricular function, preoperative renal dysfunction, postoperative use of intra-aortic balloon pumping, and postoperative induction of dialysis, while those influencing survival were previous myocardial infarction. Comparing elective CABG performed in the same period, the inhospital mortality of urgent cases was 33.8 times higher. Among hospital-survivors, patients after urgent CABG demonstrated fair long-term survival and future development of cardiac events. All efforts to achieve complete revascularization and frequent use of the internal mammary artery may contribute to improving the long-term results; however, careful management is necessary for patients with poor cardiac function.

Should we consider surgical intervention for spinal cord ischemia due to acute type B aortic dissection

We present a 46-year-old man with a sudden onset of severe back pain following leg pain. An emergent computed tomography showed acute type B aortic dissection. The true lumen was almost completely occluded because of compression of a massive thrombus in the false lumen. The patient developed paraplegia by the time he was taken into the operation room. After induction of anesthesia, partial cardiopulmonary bypass was initiated, and then the chest was opened via left thoracotomy. The entry was found in the distal aortic arch and was successfully repaired. The descending aorta was replaced with a Dacron graft and antegrade re-perfusion was established in the descending aorta three hours after the onset of paraplegia. The patient recovered uneventfully without any neurological deficit. Paraplegia caused by acute type B aortic dissection is a rare complication. Usually it is treated medically. However, if the true lumen is occluded due to a massive thrombus in the false lumen, multiple malperfusion of the distal organs may occur. In such a case, surgical intervention should be considered to resume antegrade perfusion in the descending aorta as soon as possible.

Gastric Cancer Found Incidentally during Gastroepiploic Artery Harvest

Gastric carcinoma was found incidentally while harvesting the gastroepiploic artery in 2 patients undergoing coronary artery bypass grafting. Careful examination of the stomach before harvesting the gastroepiploic artery is mandated, and if any masses are detected, an alternative conduit should be used.