Atsuo Maekawa

Overexpression of calpastatin by gene transfer prevents troponin I degradation and ameliorates contractile dysfunction in rat hearts subjected to ischemia/reperfusion

Calpain is a Ca(2+)-activated neutral protease that supposedly plays a key role in myocardial dysfunction following ischemia/reperfusion, by degrading certain proteins involved in the contraction mechanism. It is possible that overexpression of calpastatin, an endogenous calpain inhibitor, lessens contractile dysfunction in the heart after reperfusion by preventing cardiac troponin I (TnI) degradation. This claim is tested by overexpression of human calpastatin (hCS) in rat hearts ex vivo using an adenovirus vector; the hearts were transplanted heterotopically into the abdomens of recipient rats to allow expression of hCS. On the fourth day after surgery, the hearts were excised and perfused in vitro to study their recovery from 30 min of global ischemia, which was followed by 60 min of reperfusion. The peak recovery of the left ventricular developed pressure (LVDP), and the values of its first derivative (max dP/dt, min dP/dt) in the hCS-overexpressed hearts were 88.9 +/- 4.8%, 90.8 +/- 9.2% and 106.4 +/- 9.8%, respectively; these values were all significantly greater than in the control hearts transfected with LacZ alone (51.4 +/- 6.9%, 52.6 +/- 8.1% and 54.7 +/- 6.6%, P < 0.05). In western blot analysis of ventricular myocardial samples (at 60-min reperfusion) using a monoclonal anti-TnI antibody, two bands corresponding to intact TnI (30 kDa) and TnI fragments (27 kDa) were distinguished. The fraction of 27-kDa TnI (percent of total TnI immunoreactivity) in hCS-overexpressed hearts was significantly less than the controls (5.7 +/- 2.7% vs. 18.1 +/- 3.2%, P < 0.05), implying a protective action of hCS against TnI degradation. These results suggest that adenovirus-mediated overexpression of hCS in the heart could be a novel biological means to minimize myocardial stunning by ischemia/reperfusion.

Right infraaxillary thoracotomy for minimally invasive aortic valve replacement.

Minimally invasive aortic valve replacement has been performed via partial sternotomy, the parasternal approach, and anterior intercostal approaches. We successfully performed aortic valve replacement through a small right infraaxillary thoracotomy in 25 patients, with the aid of a thoracoscope and a knot-pusher. The patients were 9 men and 16 women with a mean age of 72.6 years. Our approach had better cosmetic results than traditional approaches through the anterior chest wall. This method did not require rib transection or sacrifice of the internal thoracic artery.

Spinal cord protection during a thoracoabdominal aortic repair for a chronic type B aortic dissection using the aortic tailoring strategy

This study evaluated the clinical advantage of a novel technique to reconstruct a true lumen with aortic wall tailoring for aortic repair (aortic tailoring) or the reimplantation of intercostal arteries (vascular tube) in a chronic type B aortic dissection. Thirty-three consecutive extended thoracoabdominal aortic repairs have been performed for chronic type B dissection since 2000. The novel strategy was applied in 17 cases since 2004 including eight cases of aortic repair (group A) and nine cases of a vascular tube (group B). The other 16 cases were graft interposition in five and no reimplantation in 11 for group C. There were no surgical deaths in either group A or B, and only one late death in group C. No patients sustained transient or permanent paraplegia in group A and B, while three cases of paraplegia occurred in group C (18.8%). All of the intercostal arteries were well preserved in group A and an average of 9.8 intercostal arteries for nine patients were reimplantated in group B. The present technique can optimally preserve the intercostal arteries maximally and showed an excellent surgical mortality and morbidity, especially with regard to the protection of the spinal cord.

Entire septal patch technique for postinfarction ventricular septal rupture

Postinfarction ventricular septal rupture is still a surgically challenging situation with high operative mortality. We report a case of ventricular septal rupture in a 75-year-old woman successfully treated with our newly devised technique, in which a pliable large septal path is fixed with transmural sutures placed in posterior left ventricular free wall and anterior ventriculotomy closing sutures, thus covering the septal wall almost entirely. Our method may simplify the operation and reduce the risk of residual leakage.

Use of an Expanded Polytetrafluoroethylene Patch as an Artificial Leaflet in Mitral Valve Plasty: An Early Experience

PURPOSE The purpose of this study was to examine the usefulness of polytetrafluoroethylene (PTFE) patches as artificial mitral leaflets in complex mitral valve plasty. DESCRIPTION Nineteen patients (mean age, 66 +/- 9 years) who were in need of mitral valve replacement successfully underwent mitral valve plasty with enlargement of the basal anterior leaflet using a PTFE patch. EVALUATION Operative and in-hospital mortality was 0%. Patients were followed-up by maintaining their history, physical examinations, and echocardiography. The mean follow-up period was 30 +/- 15 months (2 to 52 months) with one late mortality and one reoperation. A thin neointimal layer was observed on the explanted PTFE patch. The PTFE patch maintained its pliability with no signs of calcification, excessive thickening, or perforation for 4 years. Mean motion angle of the patch on echocardiography decreased from 41.1 +/- 10.6 to 35.2 +/- 12.5 degrees (p < 0.05) during 26.7 +/- 15.5 months of study (range, 6-46 months). The mean mitral valve area was 2.9 +/- 0.7 cm(2) at last follow-up. CONCLUSIONS The PTFE patches may be a promising material for artificial mitral leaflets.

Three-port (one incision plus two-port) endoscopic mitral valve surgery without robotic assistance†

OBJECTIVES Totally endoscopic minimally invasive mitral valve surgery (MIMVS) is technically demanding and often performed with robotic assistance. We hypothesized that three-port video-assisted thoracic surgery (VATS) would facilitate endoscopic MIMVS and evaluated its feasibility and safety. METHODS From October 2010 to June 2016, we performed first-time MIMVS in 250 consecutive patients (122 male), with median age of 65 years (54-73 years, 25-75 percentile). The thoracic access ports comprised one small (3-5 cm) thoracotomy without a rib spreader plus two trocars (one for the endoscope and one for left-handed instruments), thus establishing triangular three-port VATS. Cannulas, an aortic clamp, and a left atrial retractor were inserted through the thoracotomy, and right-handed instruments were inserted through the remaining space. Cardiopulmonary bypass was established through a groin incision. RESULTS The etiology of the mitral valve lesion was myxomatous degeneration in 70% of patients, rheumatic disease in 9%, infectious endocarditis in 6%, and other conditions in 15%. Mitral valve repair was performed in 233 patients and replacement in 27. Two patients underwent conversion to replacement after attempted repair. Forty-nine patients underwent tricuspid annuloplasty, and 45 underwent the Maze procedure. One in-hospital death occurred within 30 days. Two patients developed stroke, three underwent re-exploration for bleeding, one developed low output syndrome, and one required new haemodialysis. The aortic clamp, bypass, and total operation times were 119 (94-149), 166 (134-200) and 237 (204-285) min, respectively, median (25-75%). The 5-year survival and reoperation-free rates were 98.3% ± 0.9% and 96.9% ± 1.2%, respectively. CONCLUSIONS Three-port endoscopic MIMVS appears reproducible and safe.

Effect of modified proximal anastomosis of the free right internal thoracic artery: piggyback and foldback techniques

OBJECTIVES Few studies have reported the free right internal thoracic artery (RITA) being used in an aorto-coronary fashion. This study aimed to evaluate the free RITA with modified proximal anastomosis in an aorto-coronary fashion. METHODS Between January 2000 and December 2012, 282 patients underwent coronary artery bypass grafting with bilateral internal thoracic arteries for complete revascularization of the left coronary system at our institution. The left internal thoracic artery (LITA) was anastomosed to the left anterior descending artery (LAD) and the RITA was anastomosed to the left circumflex branches (LCX). The RITA was used as a free graft in 213 patients (free group) and as an in situ graft in 69 patients (in situ group). Proximal anastomosis of the free RITA onto the ascending aorta was performed in two different ways. We compared early and late results and graft patency of the free RITA with those of the in situ RITA retrospectively. RESULTS The numbers of anastomoses per patient and anastomoses of the RITA were larger in the free group than in the in situ group (P < 0.01). There was no significant difference in postoperative survival between the groups (free group: 93.3% vs in situ group: 90.0%, P = 0.82). The 5-year patency of the free RITA was higher than that of the in situ RITA (97.0 vs 80.3%, P = 0.01). The 5-year patency of the free RITA was comparable with that of the in situ LITA anastomosed to the LAD (97.0 vs 92.9%, P = 0.28). CONCLUSIONS The free RITA anastomosed to the LCX might have better late patency than the in situ RITA. The free RITA with modified proximal anastomosis in an aorto-coronary fashion enables complete revascularization of the left coronary system with the in situ LITA to the LAD.

Right infra-axillary mini-thoracotomy for aortic valve replacement.

Minimally invasive aortic valve replacement (MICS-AVR) has traditionally been performed through fore-chest approaches, including partial sternotomy, parasternal thoracotomy, or anterior inter-costal thoracotomy (1-3). Proximity to the ascending aorta and aortic valve seems to be advantageous in these approaches. Fore-chest skin incisions are not necessarily ideal, as minimally invasive surgery may be preferred over standard sternotomy for cosmetic reasons. However, fore-chest wounds can easily be recognized and their dimensions determined. Second, incisions in fore-chest skin tend to lead to hypertrophic scarring, as is the case in the shoulder or pubic regions. Meanwhile in minimally invasive mitral valve surgery, the antero-lateral thoracotomy is now a standard procedure irrespective of its remoteness from the mitral valve. Right antero-lateral or lateral thoracotomy is cosmetically better because the wound can be hidden by the breast or arm, and those areas are not susceptible to scar formation. We started right infra-axillary mini-thoracotomy for minimally invasive AVR (TAX-AVR) as previously reported (4). Its cosmetic superiority over standard sternotomy was apparent, and remoteness from the ascending aorta was compensated for by using long-shafted minimally invasive instruments and high definition endoscopic assist.

Atherosclerotic arch aneurysm operations with perfusion toward the aortic valve.

BACKGROUND The study objective was to investigate the efficacy of perfusion toward the aortic valve in patients who had undergone total arch replacement for atherosclerotic arch aneurysms. METHODS Transesophageal echocardiography was used to measure the peak velocities of each perfusion method in the aortic arch. The latest 15 patients with perfusion toward the aortic valve in the arch procedure were compared with 15 patients with perfusion toward the aortic arch in other cardiac operations as controls. Between April 2005 and February 2009, 65 consecutive patients underwent total arch replacement for atherosclerotic aneurysms. Among them, 48 patients underwent operations with perfusion toward the aortic valve and were reviewed. RESULTS The peak forward aortic flow velocities with perfusion toward the aortic valve were 48 +/- 26 cm/s before cardiopulmonary bypass and 29 +/- 13 cm/s on cardiopulmonary bypass. The velocities with perfusion toward the aortic arch were 67 +/- 28 cm/s before cardiopulmonary bypass and 226 +/- 114 cm/s on cardiopulmonary bypass (p < 0.001). Of the 48 patients with perfusion toward the aortic valve, postoperative temporary and permanent neurologic dysfunctions occurred in 4 (8.2%) and in 1 (2.0%), respectively. One (2.0%) hospital death occurred. CONCLUSIONS Perfusion toward the aortic valve resulted in a significant decrease in peak forward aortic flow velocity in the aortic arch during cardiopulmonary bypass, which might reduce the risk of erosion or disruption of existing atheroma and ensuing embolic complications in patients with atherosclerotic aneurysm.

Seamless reconstruction of mitral leaflet and chordae with one piece of pericardium.

OBJECTIVES Mitral valve repair is challenging when enough pliable mitral leaflets and chordae are not left intact because of extensive infective endocarditis or chronic sclerotic degeneration. For those cases, we developed a simple method to reconstruct defective leaflets and chordae en bloc with a piece of pericardium, and the mid-term results were evaluated. METHODS From January 2009 to November 2013, 25 patients with the mean age of 63 (range 20-88) years underwent this operation. The causes of mitral regurgitation were infective endocarditis in 8, sclerotic degeneration in 8, leaflet dehiscence of previous repair in 2, mitral annular calcification in 3, rheumatic in 2 and congenital in 2. After complete debridement of infected or consolidated tissue, we reconstructed defective mitral leaflets and chordae en bloc with a piece of glutaraldehyde-treated autologous pericardium. To substitute posterior leaflet and chordae, the pericardium was trimmed into a narrow pentagonal shape. The pointed end was attached directly to the corresponding papillary muscle, basal side edges to remnant leaflets on both sides, and the base to the annulus. For anterior leaflet, the pericardium was trimmed into a triangular shape if the lesion was confined in the left or right half or into a double-triangle shape if the lesion involved whole anterior leaflet. The summit of triangle was fixed to corresponding papillary muscle, and the base to remnant anterior leaflet, thus reconstructing coaptation zone and chordae seamlessly. RESULTS There was no hospital death, and mitral regurgitation at discharge was none or trivial in all patients. During 1-59 months (mean 12.7) of complete follow-up, death, infection or hemolysis was not observed. In one patient, mitral regurgitation recurred 8 months postoperatively because the fixation suture of the pericardium to the papillary muscle broke. The valve was re-repaired with re-attaching the leg of the pericardium. Regurgitation was less than moderate in all other patients. One patient with rheumatic lesion who underwent anterior leaflet repair and Maze operation suffered minor stroke 1 month postoperatively but fully recovered. CONCLUSIONS Seamless reconstruction of leaflets and chordae with pericardium seemed promising to repair extensively destructed mitral valve.