Manabu Sakurai

Physicochemical, Morphological and Therapeutic Evaluation of Agarose Hydrogel Particles as a Reservoir for Basic Fibroblast Growth Factor

Micron-sized agarose hydrogel particles were prepared using an emulsification/gelation method as a controlled release reservoir for basic fibroblast growth factor (bFGF). Mean particle size of agarose hydrogel particles decreased with an increase in stirring speed and also with an increasing temperature of the oil phase, as measured before cooling. Morphologies of agarose particles before and after dispersing into water were investigated by scanning electron microscopy (SEM) and cryogenic SEM, respectively. Freeze-dried agarose particles were spherical with rough surface. Porous polymer matrix structure was observed in the hydrogel particles by cryo-SEM. More than 99% of bFGF was encapsulated and the release from the agarose hydrogel particles was less than 3% during the incubation in phosphate buffered saline. bFGF molecules were not only adsorbed on the particle surface but also permeated and retained within the matrix. The therapeutic efficacy of bFGF retained in agarose hydrogel particles was significantly higher than that dissolved in saline. Agarose hydrogel particle seems to be a potential candidate for a bFGF reservoir.

Medium-term neurological complications after off-pump coronary artery bypass grafting with and without aortic manipulation.

BackgroundThis study aimed to assess the impact of aortic manipulation during off-pump coronary artery bypass (OPCAB) on neurological complications. Methods and resultsOf 336 isolated OPCAB surgeries, the aorta was untouched in 264 cases (group A), whereas it was manipulated by a side-biting clamp in 72 (group B). The average follow-up was 2.9±2.5 years. One patient in each group developed postoperative stroke (P=0.38). The prevalence of triple-vessel disease (group A 40.9% vs. group B 61.1%; P=0.0003) and left main trunk disease (group A 30.7% vs. group B 47.2%; P=0.1) was lower in group A than in group B. The number of bypass grafts (group A 2.18±0.97 vs. group B 3.00±0.97; P=0.0001) was lower in group A than in group B. The prevalence of preoperative atrial fibrillation and the incidence of new-onset postoperative atrial fibrillation were not different between groups (P=0.74 and 0.86, respectively). Survival rate and freedom from major adverse cardiac events were not different between groups (P=0.87 and 0.51, respectively). However, freedom from neurological complications was significantly lower in group A (P=0.0006). The Cox hazard model showed that aortic manipulation (P=0.004; odds ratio, 6.18; 95% confidence interval, 1.8–21.6) and preoperative atrial fibrillation (P=0.001; odds ratio, 14.0; 95% confidence interval, 2.7–72.5) were risk factors for neurological complications. ConclusionAlthough there was no difference in the incidence of immediate postoperative neurological complications, there were fewer medium-term neurological complications in OPCAB cases without aortic manipulation.

Pitfalls of skeletonized internal thoracic artery: comparison of graft kinking between skeletonized and pedicled grafts based on postoperative angiography findings.

Abstract  Background and aim of the study: Skeletonization of the internal thoracic artery (ITA) has several advantages: sequential bypass grafting can be easily performed, and a graft of increased length can make the distal coronary artery accessible. However, kinking of the grafts has been observed on postoperative angiograms in a few cases. We investigated whether there were significant differences in the frequency of graft kinking and stenosis degree at the kink site between pedicled and skeletonized grafts. Methods: Postoperative angiography was performed for all cases. In pedicled (n = 65) and skeletonized (n = 129) groups, the results of postoperative graft angiography were analyzed to investigate the presence of graft kinking and stenosis degree at the kink site. Results: Kinking was observed in 4 (5.9%) and 9 (3.9%) arteries in the pedicled and skeletonized groups, respectively (p = 0.341). The stenosis degree at the kink site (mean ± SD) was significantly higher in the skeletonized group (47.2 ± 16.8%) than in the pedicled group (23.5 ± 13.7%), (p = 0.032). In four patients in whom early postoperative angiography showed a kink with more than 50% stenosis, late‐term angiography was performed. All four cases showed regression of the stenosis degree at the kink site. Conclusions: When the ITA had a kink, the stenosis degree at the kink site was significantly higher in the skeletonized group than in the pedicled group. Late angiography often reveals regression of stenosis at the kink site. Immediate intervention need not always be performed if the patient has no angina caused by a stenotic lesion at the kink site.

Extracardiac rupture of a sinus of Valsalva aneurysm

A 73-year-old male presented with back pain. Contrast-enhanced computed tomography (CT) and echocardiography showed a 6.8-cm sinus of Valsalva aneurysm of the non-coronary sinus and a pericardial effusion (Figure 1A and B). The patient arrested upon transfer to the operating room and required cardiopulmonary resuscitation. Cardiopulmonary bypass was emergently established via the right femoral artery and the right atrium. There was a large amount of fresh blood in the pericardium and active bleeding from the perforated sinus of Valsalva aneurysm was observed. Following cardioplegic arrest, the non-coronary sinuswas opened. Therewas no evidence of a dissection flap or any fistulas into any of the cardiac chambers. All the aortic valve leaflets were intact and the valve was competent (Figure 2). After the aneurysm was resected, the defect in the non-coronary sinus was reconstructed with a Dacron graft which was sutured along the annulus and above the attachment of the non-coronary cusp. The patient tolerated the procedure well and made a full neurologic recovery. A postop CT showed an intact patch (Figure 3) and therewas no aortic regurgitation on echocardiography. Histological examination of the aneurysmal wall showed absence of elastic fibers and necrosis, and mucoid degeneration of the media (Figure 4A and B). The patient continues to do well 6 months following surgery.

Total aortic arch grafting via median sternotomy using integrated antegrade cerebral perfusion

BACKGROUND In aortic arch grafting, antegrade cerebral perfusion prolongs the safe time of arch exclusion. However, there are the problems of cerebral embolism and distribution of the cerebral perfusion. We describe and analyze mortality and cerebral complications in patients undergoing total arch grafting using our refined technique. METHODS Between June 1994 and March 2002, 100 consecutive patients underwent total arch grafting through median sternotomy. There were 49 atherosclerotic aneurysms and 51 aortic dissections. Fifty-four patients were operated on an emergency basis because of rupture or acute type A dissection. We conducted total arch grafting using hypothermic antegrade cerebral perfusion from every cervical vessel. Carbon dioxide gas was added to the cerebral perfusion in order to inhibit the increase in the cerebral vascular resistance during hypothermic cerebral perfusion. RESULTS Hospital mortality was 4%. The causes of death were dysarrhythmia (n = 1), mesenteric necrosis (n = 1), and preoperative cardiac arrest (n = 2). On univariate analysis, preoperative shock and concomitant cardiac procedures were risk factors for hospital death. The rate of postoperative neurologic damage was 5%. Two patients suffered from cerebral infarction. Temporary neurologic dysfunction occurred in 3 patients. On univariate analysis, emergency surgery was a risk factor for postoperative neurologic damage. On multivariate analysis, there was no significant independent predictor of hospital mortality and neurologic damage. Actuarial survival at 96 months was 66.4 +/- 9.1%, and freedom from aortic accidents (reoperation, rupture, and cholesterol embolism) was 74.9 +/- 7.9%. CONCLUSIONS The early- and long-term results of total arch grafting using integrated antegrade cerebral perfusion were found to be satisfactory.

Effect of tricuspid annuloplasty concomitant with left heart surgery on right heart geometry and function

Objectives To elucidate the effect of tricuspid annuloplasty concomitant with left‐sided valve surgery on the right heart in patients with mild or more tricuspid regurgitation (TR). Methods We enrolled 78 patients with mild or more TR who underwent left‐sided valve surgery. Forty‐three patients underwent only left‐sided valve surgery (group non‐T) and 35 underwent concomitant tricuspid annuloplasty (group T). Echocardiographic changes between the preoperative and 1‐year follow‐up periods were compared. Propensity score matching was used to obtain risk‐adjusted outcome comparisons (16 pairs). Results In group non‐T, there were more operations for aortic stenosis and concomitant coronary artery bypass grafting, and fewer operations for mitral regurgitation. The prevalence of atrial fibrillation was higher in group T. In preoperative echocardiography, there were no significant differences in left ventricular and right ventricular (RV) dimensions and functions. Tricuspid valve annular diameter and TR‐related parameters were significantly larger in group T. Left ventricular dimensions and TR‐related parameters significantly improved in both groups 1 year after operation. RV diameter was significantly reduced in only group T. In analysis of variance, RV diameter in systole and diastole showed significant interaction, whereas left heart dimensions and function, tricuspid valve tethering height, and RV fractional area change did not show interaction. These results were not attenuated even after propensity‐matching analyses. Conclusions Among patients with mild or more TR, RV reverse remodeling was not obtained with left‐sided valve surgery alone. Additional use of tricuspid annuloplasty might potentially achieve favorable TR regulation as well as RV reverse remodeling.

Popliteal Artery Pseudoaneurysm Caused by Osteochondroma

A 16-year-old boy developed pulsating pain and dysesthesia in his right knee. Computed tomography showed a large aneurysm in the right upper popliteal artery and a spiked bone tumor arising from the right distal femoral shaft. Pseudoaneurysm due to osteochondroma was suspected, and the patient underwent emergency surgery. A 2-mm pinhole was detected in the arterial wall behind the tumor. After resection of the tumor, the damaged arterial wall was removed, and the defect was repaired using a saphenous vein patch. We suggest that patch repair is preferable to direct closure or end-to-end anastomosis to prevent recurrent pseudoaneurysm at a later time, even if the defect is small.

Impact of Preexisting Cerebral Ischemia Detected by Magnetic Resonance Imaging and Angiography on Late Outcome After Coronary Artery Bypass Surgery

BACKGROUND The aim of this study was to assess the impact of preexisting ischemia detected by brain magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) on long-term survival, and cardiac and neurologic events after coronary artery bypass grafting (CABG). METHODS Of 923 patients who underwent CABG between 1994 and 2007, 887 patients (96.1%) were followed up. Preoperative brain MRI and MRA were performed in 619 patients. Ischemia was detected by brain MRI and MRA in 158 patients (group A), but not in 461 patients (group B). Preoperative characteristics, follow-up survival, and cardiac and neurological events were investigated. RESULTS The average follow-up period was 6.0 ± 4.3 years. Univariate analysis showed that patients in group A (68.5 ± 6.5 years) were older than those in group B (64.5 ± 8.6 years) (p = 0.0001). Preoperative left ventricular ejection fraction was less in group A (0.516 ± 0.175) than in group B (0.556 ± 0.165) (p = 0.02). The prevalence of peripheral vascular disease was higher in group A (14 patients: 8.9%) than in group B (11 patients: 2.4%) (p = 0.001). The rate of on-pump CABG was lower in group A (115 patients; 72.8%) than in group B (383 patients; 83.1%) (p = 0.007). Survival rate was significantly lower (p = 0.062), and freedom from major adverse cardiac event or stroke were significantly lower in group A (p = 0.0002, and p = 0.0001, respectively; log-rank test). However, the Cox proportional hazard model showed that preoperative brain ischemia detected by brain MRI and MRA affected only freedom from neurologic events (p = 0.02; hazard ratio 2.52; 95% confidence interval 1.13 to 5.62), but not survival (p = 0.67) or major adverse cardiac event (p = 0.09). CONCLUSIONS Preexisting ischemic findings on brain MRI and MRA in patients who underwent CABG were related only to long-term freedom from stroke, but were not related to survival or major adverse cardiac event.

Evaluation of Early and Midterm Results of Offpump Coronary Artery Bypass in Patients with Left Main Disease

Abstract  Purpose: This study evaluated the early and midterm results of offpump coronary artery bypass (OPCAB) for left main coronary artery (LMCA) stenosis. Methods: Patients treated between November 2001 and December 2006, during which isolated coronary artery bypass grafting (CABG) was performed without cardiopulmonary bypass in principle, were included. Isolated CABG was performed in 206 patients, of whom 62 (30.1%) had LMCA stenosis >50%. Results: The in‐hospital mortality rate (LMCA stenosis > 50%, 1.6%; LMCA stenosis ≦50%, 0.7%, p = 0.512), the incidence of postoperative complications, and the midterm survival rate (LMCA stenosis≻50%, 86.7 ± 5.2%/5 years, LMCA stenosis≦50%, 89.6 ± 3.8%/5 years, p = 0.21) did not significantly differ between the two groups. Conversion was significantly frequent in patients with LMCA stenosis >75% and severe stenosis >90% in the right coronary artery (RCA) trunk. Conclusions: Patients with LMCA stenosis can undergo OPCAB safely and the midterm results are good. As conversion was significantly frequent in patients with severe LMCA and RCA trunk stenosis, adequate preparation for pump application is necessary.

Ascending aortic aneurysm following aortico-ventricular tunnel repair

Aortico-left ventricular tunnel is a very rare congenital anomaly. An 18-year-old boy had undergone tunnel closure at 3 years of age. A moderate degree of aortic regurgitation remained postoperatively. Seven years later, aortic valve replacement for aortic regurgitation was performed. Eight years later, the ascending aortic aneurysm had grown to 63 mm in diameter. This dilatation became an operative indication. Ascending aortic replacement was performed with a Dacron graft. Pathological examination of the resected aortic wall revealed cystic medial degeneration. We report a rare case of ascending aortic aneurysm following surgical repair of the aortico-left ventricular tunnel and aortic valve replacement.