Keiji Kamohara

Scaffold-Free Tubular Tissues Created by a Bio-3D Printer Undergo Remodeling and Endothelialization when Implanted in Rat Aortae

Background Small caliber vascular prostheses are not clinically available because synthetic vascular prostheses lack endothelial cells which modulate platelet activation, leukocyte adhesion, thrombosis, and the regulation of vasomotor tone by the production of vasoactive substances. We developed a novel method to create scaffold-free tubular tissue from multicellular spheroids (MCS) using a “Bio-3D printer”-based system. This system enables the creation of pre-designed three-dimensional structures using a computer controlled robotics system. With this system, we created a tubular structure and studied its biological features. Methods and Results Using a “Bio-3D printer,” we made scaffold-free tubular tissues (inner diameter of 1.5 mm) from a total of 500 MCSs (2.5× 104 cells per one MCS) composed of human umbilical vein endothelial cells (40%), human aortic smooth muscle cells (10%), and normal human dermal fibroblasts (50%). The tubular tissues were cultured in a perfusion system and implanted into the abdominal aortas of F344 nude rats. We assessed the flow by ultrasonography and performed histological examinations on the second (n = 5) and fifth (n = 5) day after implantation. All grafts were patent and remodeling of the tubular tissues (enlargement of the lumen area and thinning of the wall) was observed. A layer of endothelial cells was confirmed five days after implantation. Conclusions The scaffold-free tubular tissues made of MCS using a Bio-3D printer underwent remodeling and endothelialization. Further studies are warranted to elucidate the underlying mechanism of endothelialization and its function, as well as the long-term results.

Dual left anterior descending coronary artery: report of a case.

We report a case of Type I dual left anterior descending artery (LAD) successfully treated by coronary artery bypass grafting including the long LAD. This rare coronary artery anomaly is of clinical importance in the field of myocardial revascularization.

Splenic abscess associated with active infective endocarditis

Splenic abscess is a rare complication in infective endocarditis. Here, we present two cases of splenic abscess associated with active infective endocarditis. Body computed tomography before emergency valvular surgery revealed abscess in the spleen. In case 1, the abscess was localized within the spleen; splenectomy and valve replacement were performed through the same median skin incision. In case 2, the splenic abscess was diagnosed as ruptured; valve replacement was performed, followed by splenectomy through a separate skin incision. No recurrence of infection occurred after surgery in either case. In surgical treatment for active infective endocarditis, body computed tomography is essential to diagnose splenic abscess preoperatively. If there is an abscess, then splenectomy and valvular surgery should be performed simultaneously to prevent reinfection after valvular surgery. The approach to the spleen should be individualized according to the extension of the abscess.

Operative strategy for descending and thoracoabdominal aneurysm repair with preoperative demonstration of the Adamkiewicz artery.

BACKGROUNDnOur study aimed to demonstrate the efficacy of preoperative intraarterial computed tomographic angiography to identify the Adamkiewicz artery (AKA). We also aimed to investigate the impact of identification of the AKA on the strategy for preventing spinal cord injury.nnnMETHODSnThirty-seven patients (24 cases of descending aortic aneurysms and 13 cases of thoracoabdominal aortic aneurysms), were studied. Average age was 63.8 years old. A pigtail catheter was inserted into the descending aorta and its tip was located immediately below the left subclavian artery. Subsequently, intraarterial computed tomographic angiography was performed and the segmental artery to the AKA was identified. Aneurysms were replaced electively with prosthetic graft in all cases. In cases where the aortic segment that supplied the AKA was cross-clamped, the identified segmental artery-AKA was selectively perfused. In these cases, the segmental artery-AKA was reconstructed with an interposition graft.nnnRESULTSnIntraarterial computed tomographic angiography successfully identified the segmental artery-AKA in all patients. The average number of AKA observed per patient was 1.3± 0.6 AKAs. Selective perfusion of preoperatively identified segmental artery-AKAs was performed in 11 cases. The average number of reconstructed segmental arteries was 0.5 in descending aortic aneurysms and 1.7 in thoracoabdominal aortic aneurysms. Although paraparesis occurred in two patients (5%), the remaining 35 patients did not suffer spinal cord injury.nnnCONCLUSIONSnIntraarterial computed tomographic angiography reliably identifies the segmental-AKA. Furthermore, selective perfusion of the segmental artery-AKA, based on accurate preoperative identification, might be one option for preventing intraoperative spinal cord ischemia.

Life-saving strategy for left ventricular free wall rupture after acute myocardial infarction

OBJECTIVEnLeft ventricular free wall rupture after acute myocardial infarction is a serious complication with high mortality. For life-saving, it is important how to maintain poor hemodynamics till operation. We have consistently made it our strategy to attach percutaneous cardiopulmonary support system and intra-aortic balloon pumping immediately after the diagnosis regardless of the type of left ventricular free wall rupture and of the hemodynamic conditions, and perform an infarction-covering repair under the beating heart. We have studied the short-term and middle-term results after the operations, and have evaluated the efficacy and problems of this procedure.nnnMETHODSnSince September 1994, we have performed this method in six of eight patients with left ventricular free wall rupture.nnnRESULTSnAs results, five of the six patients (83%) were saved including two cases of blow-out type. Our strategy for left ventricular free wall rupture showed several advantages for preoperative and intraoperative maintenance of the hemodynamic conditions, and for preservation of some reversible myocardium by the simple technique of infarction-covering repair under the beating heart. These resulted in shortening the operation time, decreasing the incidence of low cardiac output syndrome, and obtaining a satisfactory rate of life-saving.nnnCONCLUSIONnWe believe that this infarction-covering repair based on our strategy is effective for life-saving during the acute period.

Operative technique for tracheo-innominate artery fistula repair

Tracheo-innominate artery fistula is fatal unless treated surgically. We describe our surgical approach and results in seven patients. The average patient age was 15.7 years; all patients had prior severe neurological deficits. Three of seven patients were in hemorrhagic shock; control of preoperative bleeding was achieved with tracheostomy tube cuff overinflation. The innominate artery and the trachea were exposed through a collar incision and partial upper sternotomy. The innominate artery was divided at the aortic arch and at the bifurcation, with one exception. Cerebral blood flow was monitored by the blood pressure difference in the bilateral upper extremities and by near-infrared spectroscopy. The tracheal fistula was left adherent to the innominate artery in all but one patient. All patients were discharged without new neurologic deficits or severe morbidity. Overall survival was 84% at 37 months, without any vascular, tracheal, or neurological events.

Surgical Strategy for Retrograde Type A Aortic Dissection Based on Long-Term Outcomes

BACKGROUNDnThe optimal management of a retrograde type A aortic dissection (RAAD) is controversial, and few reports have discussed the long-term outcomes of surgical strategies. To determine the most appropriate strategy, we studied the early and late outcomes of RAAD cases.nnnMETHODSnFrom 1998 to 2014, 44 patients with RAAD (mean age of 63 ± 11 years) underwent surgical repair. Ascending aortic replacement (AAR) was performed in 21 patients and ascending and total arch replacement (TAR) was performed in 23 patients. Eight of the patients who received TAR underwent complete resection of the primary tear in the distal arch or descending aorta (TAR-R[+]), whereas the remaining 15 patients received elephant trunk implantation as an alternative procedure for tear resection (TAR-R[-]). The early and late outcomes (mean follow-up, 86.5 months) were evaluated.nnnRESULTSnHospital mortality occurred in 4 of the 44 (9.1%) patients, with no mortalities among the patients undergoing TAR-R[-]. There was a tendency toward a higher incidence of late aorta-related events in the AAR group, with a significantly higher patency rate of the false lumen in the proximal site of the residual aorta compared with the TAR group (p = 0.009). Furthermore, the 5-year rate of freedom from aortic growth greater than 50 mm was significantly lower after AAR than after TAR (p = 0.04). A multivariate analysis indicated that the initial ascending aortic diameter (odds ratio [OR], 1.5; p = 0.02) and AAR (OR, 29.1; p = 0.01) were independent predictors of late aortic expansion.nnnCONCLUSIONSnThe surgical outcomes were acceptable in both the AAR and TAR groups. The long-term outcomes potentially support the aggressive adoption of TAR in relatively younger patients with significant ascending aortic enlargement at presentation.

Real-Time Three-Dimensional Transesophageal Echocardiography Is Useful for the Localization of a Small Mitral Paravalvular Leak

The use of multiplane transesophageal echocardiography (TEE) to reconstruct 3-dimensional (3D) images is limited by time-consuming, multiplane image acquisition and the need for offline processing. To overcome these limitations, a 3D fully sampled matrix array transducer was recently developed to allow real-time acquisition and online display of 3D images. In this case, real-time 3D transesophageal echocardiography produced clear image of a small paraprosthetic leak point. Although the surgical view from the left atrium was poor due to severe adhesions, we were able to perform optimal repair of the small leak after intraoperative confirmation of the location of the leak that was identified by preoperative real-time 3D transesophageal echocardiography.

Mitral Annular Reconstruction

Mitral annular reconstruction using a pericardial patch was performed in 3 cases of atrioventricular disruption. This technique may be useful for atrioventricular disruption in cases of active endocarditis, redo valve replacement, left ventricular rupture after mitral valve replacement, and annular calcification.

Mital valve regurgitation with anterior mitral leaflet chordal rupture or elongation —Repair using the flip over technique—

Repair of prolapsed anterior mitral leaflet has remained technically difficult. The purpose of this study was to assess the clinical results after using the flip-over technique for patients with anterior mitral leaflet prolapse due to dhordal rupture or elongation. Between January 1993 and September 1997, fifteen adult patients with pure mitral valve regurgitation (MR) due to prolapse of the anterior mitral leaflet underwent repair using the flip-over technique. The indication for this procedure were; 1) all mitral structures except the prolapsed area must appear to be intact, and 2) the corresponding chordae attached to the posterior leaflet should be sufficiently strong to be transferred to the anterior leaflet. The prognoses following this technique were retrospectively studied to assess the early and mid-term clinical outcome of this procedure. Follow up was complete in all patients and ranged from 2 to 56 months (with a mean of 25 +/- 17.9 months). There was no hospital death, None required reoperation. One patient died because of acute recurrent MR during follow-up. No other complication was experienced. Doppler echocardiographic studies at the final follow-up showed less than mild regurgitation in 11 (78.6%) of the 14 surviving patients. We believe that this procedure was effective for that the obtained repair of a prolapsed anterior mitral valve and early and mid-term clinical outcome from this procedure has been satisfactory.