Toshifumi Murashita

Anomalous origin of the left coronary artery from the pulmonary artery in an adult: tubular reconstruction of the left main coronary artery under coronary perfusion.

Abstract A 38‐year‐old female with anomalous origin of the left coronary artery (LCA) from pulmonary artery was surgically corrected by tubular reconstruction of the left main coronary artery (LMCA) using the pulmonary artery wall, and this repair was performed under beating heart. Thus, the pulmonary artery was divided above the orifice level and just above the pulmonary valve, and the commissure between nonfacing and left side sinuses was dissected away from the pulmonary artery wall to obtain lateral flaps. The pulmonary artery defect was reconstructed with a roll using an autologous pericardial patch, while the detached commissure was suspended on the pericardial patch. The long tube constructed using pulmonary artery tissue was anastomosed to the anterior aspect of the ascending aorta. These procedures were performed under beating heart simply by clamping the LMCA, since the preoperative myocardial contrast echocardiography confirmed the adequate coronary collateral flow from the right circulation. The postoperative course was uneventful, and a coronary artery angiogram demonstrated a widely patent LMCA. Our experience suggests that, in adult cases, this procedure could be performed without myocardial ischemia simply by clamping the LMCA because of well‐developed coronary collateral arteries. The safety of this technique could be confirmed by myocardial contrast echocardiography.

Long-term results of aortic valve regurgitation after repair of ruptured sinus of valsalva aneurysm

BACKGROUND We reviewed our 35-year-experience to investigate the determinants of long-term results of aortic valve regurgitation (AR) after surgical repair of ruptured sinus of Valsalva aneurysms (RSVA). METHODS Between 1963 and 1998, a total of 35 patients aged 7 to 64 years underwent surgery for RSVA. The aneurysms ruptured into the right ventricle (n = 24), right atrium (n = 10), and left atrium (n = 1). In all, 19 patients had VSD and 9 patients had AR. A combined approach through aortotomy and the involved chamber was used for 24 patients. Either direct (n = 19) or patch (n = 16) closure was used to close the rupture hole. The AR was graded on a scale of 0 to IV by angiographic or echographic evaluation. RESULTS There were no early deaths. Late death occurred in 1 patient, whose AR deteriorated to grade III 20 years later. Two patients (5.7%) required reoperations on the aortic valve, because grade III AR was noted 8 and 26 years after operation, respectively. Freedom from postoperative grade III AR or higher was 93% at 10 years and was 87% at 20 years. Late AR was associated with preoperative and early postoperative AR (p < 0.05) but not with the presence of VSD, location of the fistula, surgical approach, or type of repair (direct vs patch). Multivariate analysis indicated that early postoperative AR was the only independent variable. CONCLUSIONS Late AR necessitating reoperation still confers significant risk in the long-term follow-up after repair of RSVA. No particular risk factor of preoperative conditions and surgical methods was elucidated in this study, and postoperative AR at discharge from the hospital was the only factor determining the long-term results of AR.

Postoperative renal function after elective abdominal aortic aneurysm repair requiring suprarenal aortic cross-clamping.

PurposeTo examine postoperative renal function after suprarenal aortic cross-clamping performed without renal hypothermia in patients undergoing elective abdominal aortic aneurysm (AAA) surgery.MethodsBetween 1991 and 2000, 18 patients underwent surgery for a juxtarenal AAA, which required a suprarenal aortic cross-clamp. All AAAs were repaired with a proximal anastomosis just below the renal arteries. We divided the patients into two groups according to the duration of the renal ischemia: <45 min (n = 12) and ≥45 min (n = 6). The postoperative changes in renal function were analyzed.ResultsThere were no hospital deaths and none of the patients needed permanent hemodialysis. The postoperative peak in the serum creatinine level after suprarenal cross-clamping for ≥45 min was significantly higher than that after cross-clamping for <45 min. The percentage changes in serum creatinine and blood urea nitrogen were correlated positively with the duration of renal ischemia, and were significantly greater in the group with renal ischemia of <45 min than in the group with prolonged renal ischemia (≥45 min).ConclusionsSuprarenal aortic cross-clamp without performing renal hypothermia is safe and able to be tolerated well by the patient during elective AAA surgery, although careful attention must be paid to limiting the period of renal ischemia.

Increased lung injury in pulmonary hypertensive patients during open heart operations

To investigate lung injury in adult open heart operations during extracorporeal circulation, we measured plasma chemiluminescence levels. Nineteen patients were divided into two groups depending on preoperative pulmonary artery pressure: a pulmonary hypertension group (n = 11) and a control group (n = 8). Plasma samples were taken simultaneously from arterial and central venous lines at six different points during and early after operation. Arteriovenous difference of chemiluminescence (counts/10 seconds) increased significantly only in the pulmonary hypertension group (from -19.1 +/- 8.3 at the end of cross-clamping to 23.7 +/- 12.4 at the end of bypass; p < 0.01). There was a positive correlation between peak values of arterial plasma chemiluminescence and postoperative respiratory index in the pulmonary hypertension group (p < 0.05). In addition, during the first 12 hours postoperatively, arteriovenous difference of chemiluminescence in the pulmonary hypertension group changed significantly from negative to positive values (p < 0.05). These data suggest that free radical activity (detected by chemiluminescence) was deeply involved in lung injury during and also early after open heart operations, especially in pulmonary hypertensive patients.

Use of bioresorbable membrane to prevent postoperative small bowel obstruction in transabdominal aortic aneurysm surgery.

PurposeTo evaluate the efficacy of Seprafilm (Genzyme, Cambridge, MA, USA), a bioresorbable membrane, in preventing or reducing early postoperative small bowel obstructions after transabdominal abdominal aortic aneurysm (AAA) surgery.MethodsFifty-one patients underwent aortic reconstruction via a midline transperitoneal approach for infrarenal AAAs. Twenty-one patients underwent surgery with Seprafilm (Seprafilm group) and the remaining 30 patients did not (control group). The incidence of early small bowel obstruction was examined, and the time before liquid and solid diet were resumed was also compared to assess postoperative paralytic ileus.ResultsPatients in the Seprafilm group resumed a liquid diet on postoperative day (POD) 2.4 ± 1.1 and a solid diet on POD 4.0 ± 1.3, whereas the patients in the control group resumed a liquid diet on POD 3.3 ± 1.9 and a solid diet on POD 5.4 ± 3.4. These values were not significantly different between the two groups; however, the incidence of early postoperative small bowel obstruction was significantly lower (P < 0.05) in the Seprafilm group (0/21) than in the control group (6/30).ConclusionThese findings suggest that Seprafilm may help to prevent early postoperative small bowel obstructions after transabdominal AAA surgery.

Surgical management of atherosclerotic aortic arch aneurysms using selective cerebral perfusion: 7-year experience in 52 patients

OBJECTIVE Patients with atherosclerotic aortic arch aneurysms are at greater risk for brain complication. We report our techniques and results of operation using selective cerebral perfusion. METHODS We retrospectively analyzed 52 consecutive patients with atherosclerotic aortic arch aneurysms (mean age, 70 years, range, 53-86 years), who underwent operation between April 1992 and March 1999. The operation was non-elective in 11 patients (21.1%). Concomitant operations included eight coronary artery bypass grafting and one aortic valve replacement. Simultaneous distal aortic reconstruction was performed in three patients. The operation was performed through median sternotomy. To avoid brain embolism, total arch replacement with a branched prosthesis was performed in 48 patients, in an attempt to exclude affected segments of aorta. In addition, retrograde femoral artery perfusion was avoided and cerebral circulation was isolated before aortic manipulation. To achieve even blood flow distribution, we employed perfusion and continuous pressure monitoring of all the three arch vessels. The perfusion rate was 12+/-2 ml/kg per min and the pressure was kept around 50 mmHg. Deep hypothermic arrest of the lower torso (bladder temperature, 22 degrees C) was used during open distal aortic anastomosis. RESULTS The hospital mortality rate was 11.5% (six of 52), and 7.3% (three of 41) for elective cases. Only one patient (1. 9%) developed permanent focal neurological deficit. Six other patients showed temporary brain complications, which was global (delirium) in three and focal in three others. CONCLUSIONS Selective cerebral perfusion is a safe brain protection method, and our strategy seems effective for embolic stroke prevention.

Improved healing of small-caliber, long-fibril expanded polytetrafluoroethylene vascular grafts by covalent bonding of fibronectin

PurposeTo evaluate the intermediate performance of small-caliber, long-fibril expanded polytetrafluoroethylene (ePTFE) vascular grafts pretreated with covalent bonding of fibronectin in dogs.MethodsSmall-caliber (4 mm), long-fibril (60 µm), ePTFE vascular grafts, 10 cm in length, were pretreated by covalent bonding of fibronectin. Bilateral iliac grafting was done in dogs using a fibronectin-bonded graft on one side and a nonbonded control graft on the other side. The grafts were retrieved 12 weeks after implantation, and subjected to histomorphometric analysis.ResultsAlthough the patency rates of the fibronectin-bonded and control grafts were the same (3/7, 43%), the fibronectin-bonded grafts showed almost complete neointimal healing, whereas the nonbonded control grafts showed only partial neointimal healing, proximally and distally.ConclusionsSmall-caliber, long-fibril ePTFE vascular grafts with covalent bonding of fibronectin achieved almost complete neointimal healing by the time of retrieval at 12 weeks. This indicates that, with further modifications, our new technique for covalent bonding of fibronectin has great potential in the development of small-caliber arterial prosthetic grafts.

Wavelet analysis of bileaflet mechanical valve sounds

It has been reported that asynchronous leaflet closure in a bileaflet mechanical valve causes a split in the valve closing sound. We have previously reported that the continuous wavelet transform (CWT) with the Morlet wavelet as modified by Ishikawa (the Morlet wavelet) is the most suitable method among the CWTs for detecting a split in the bileaflet mechanical valve sound because this method can detect the highest frequency signal among the CWT methods with higher time resolution. This is the first article which discusses the acoustic properties of five types of bileaflet valves using the Morlet CWT. Similar behavior of the valve sound split intervals with wide fluctuations over consecutive heartbeats was found to be the common finding for all the bileaflet valves. This result suggests that fluctuation of the split interval proves the normal movement of both leaflets without movement disturbance. The mean differences in the split interval between these bileaflet valves were statistically significant, and the wavelet coefficients of the CWT showed characteristic scalographic patterns, such as a teardrop shape or a triangle beneath the split. However, these two findings gave no valuable information for the diagnosis of bileaflet valve malfunction. A split in the valve closing sound with a fluctuating interval was the common finding in these five normally functioning bileaflet valves, and careful observation of the splits behavior may be a key to diagnosis of bileaflet valve malfunction.

Quantitative gated myocardial perfusion single photon emission computed tomography improves the prediction of regional functional recovery in akinetic areas after coronary bypass surgery: useful tool for evaluation of myocardial viability

OBJECTIVE Assessment of myocardial viability in akinetic areas is essential in surgery for ischemic heart disease, including coronary artery bypass grafting and left ventriculoplasty. The aim of this study is to evaluate the utility of quantitative indices of perfusion uptake, wall motion, and wall thickening of each region calculated by quantitative electrocardiogram-gated single photon emission computed tomography (SPECT) for prediction of functional recovery after coronary artery bypass grafting. METHODS Forty patients scheduled for coronary artery bypass grafting were prospectively included. Electrocardiogram-gated SPECT was performed before and 1 week and 3 months after operation, and coronary angiography was performed before and after operation. The myocardium was divided into 9 segments and myocardial viability, assessed by improvement of the wall motion score using a cine mode display, and evaluated by radionuclide criteria (perfusion uptake, wall motion, wall thickening). Twenty-four segments with moderate hypokinesis and 14 segments with akinesis with patent grafts were assessed. RESULTS All segments with moderate hypokinesis except 1 (96%) had improved wall motion scores postoperatively, whereas of 14 segments with akinesis only 7 segments (50%) had improved wall motion scores. The preoperative perfusion uptake in the improved segments was significantly higher than in the nonimproved segments (62.7% +/- 15.6% vs 46.4% +/- 24.5%, P =.01). There was a significant difference in wall motion between the improved and nonimproved segments (3.8 +/- 2.2 mm vs 1.4 +/- 1.4 mm, P =.001), and the preoperative wall thickening of the improved segments was significantly higher than in the nonimproved segments (27.2% +/- 14.1% vs 8.2% +/- 10.3%, P <.0001). The optimal cutoff level of perfusion uptake was 50%, with the highest accuracy of 72%, and the optimal cutoff levels of wall thickening and wall motion were 10% and 1.5 mm, with the highest accuracies of 76% and 85%, respectively. CONCLUSION The regional functional index calculated by electrocardiogram-gated SPECT indicated that wall thickening was well correlated with functional recovery compared with wall motion or perfusion uptake. This suggests that the wall thickening calculated by electrocardiogram-gated SPECT may be more useful to predict functional recovery than regional myocardial perfusion. Or, it could suggest that in addition to perfusion uptake, wall thickening could enhance the objective assessment of myocardial viability.

Giant pseudoaneurysm of the right ventricular outflow tract after repair of truncus arteriosus: evaluation by MR imaging and surgical approach

One year after surgical repair of the truncus arteriosus, a 1-year 8-month-old boy was found to have a pseudoaneurysm of the right ventricular outflow tract (RVOT). Cine-magnetic resonance imaging (MRI) showed a narrow communication between the RVOT and aneurysm. MRI was useful to evaluate the anatomical and spatial relations between the pseudoaneurysm and the surrounding structures, therefore an appropriate approach was chosen. Thus, a median sternotomy approach was carried out and ordinary central cannulation was feasible to establish a cardiopulmonary bypass. The defect was successfully repaired with reconstruction using a monocuspid outflow patch. MRI provided useful information for deciding the surgical approach.