Tomoki Shimokawa

Right-Sided Partial Sternotomy for Minimally Invasive Valve Operation: “Open Door Method”

A simple technique for minimally invasive valve operations is described. With a 10-cm midline skin incision, excellent exposure of both the mitral and aortic valves is achieved through a right-sided partial sternotomy, which enables us to perform easy repair or replacement of these valves.

Influence of carotid artery stenosis on stroke in patients undergoing off-pump coronary artery bypass grafting

OBJECTIVE It is well known that the presence of carotid artery stenosis increases the risk of perioperative stroke in patients undergoing cardiac surgery with cardiopulmonary bypass. Although off-pump coronary artery bypass grafting (CABG) can avoid the adverse effects of cardiopulmonary bypass, the influence of carotid artery stenosis on the incidence of stroke in patients undergoing off-pump CABG has not been well clarified. METHODS We conducted a retrospective study of 461 patients who underwent elective off-pump CABG after screening for carotid artery stenosis at our institute between September 2004 and May 2007. The incidence and etiologies of stroke were identified. Preoperative screening revealed significant carotid artery stenosis in 49 patients. Clinical results were compared between patients with and without carotid artery stenosis. RESULTS Postoperative stroke occurred in two (0.43%) of the 462 study patients, and in-hospital mortality occurred in three (0.65%). Stroke was due to decreased perfusion resulting from hypovolemic shock in one and thrombosis in the other. There was neither stroke nor in-hospital mortality in patients with carotid artery stenosis, although there were two strokes (0.49%) and three in-hospital mortalities (0.73%) in patients without carotid artery stenosis. CONCLUSIONS The influence of carotid artery stenosis on the incidence of perioperative stroke may be little in off-pump CABG, especially in patients with moderate carotid artery stenosis.

Coronary artery bypass surgery versus percutaneous coronary artery intervention in patients on chronic hemodialysis: does a drug-eluting stent have an impact on clinical outcome?

Abstract  Coronary revascularization methods continue to be refined, and the emergence of the drug‐eluting stent (DES) has especially changed clinical practice related to ischemic heart disease. For chronic hemodialysis (HD) patients, however, the impact of DES on clinical outcome is yet to be determined. Forty‐six consecutive chronic HD patients who underwent myocardial revascularization in our institute were retrospectively reviewed. Twenty‐eight patients underwent coronary artery bypass surgery (CABG) and 18 patients underwent percutaneous coronary artery intervention (PCI). Patient characteristics were similar between the two groups. In the CABG group, bilateral internal thoracic artery (ITA) bypass grafting was performed in 27 patients and off‐pump CABG was performed in 20 patients. In the PCI group, a DES was used in 12 patients. The number of coronary vessels treated per patient was higher in the CABG group (CABG: 4.25 ± 1.32 vs. PCI: 1.44 ± 0.78; p < 0.001). Two‐year survival rates were similar between the two groups (CABG: 94.1% vs. PCI: 73.9%; p = 0.41), but major adverse cardiac event‐free survival (CABG: 85.9% vs. PCI: 37.1%; p = 0.001) and angina‐free survival (CABG: 84.9% vs. PCI: 28.9%; p < 0.001) rates were significantly higher in the CABG group. The one‐year patency rate for the CABG grafts was 93.3% (left ITA: 100%, right ITA: 84.6%, sapenous vein: 90.9%, gastro‐epiploic artery: 100%), and six‐month restenosis rate for PCI was 57.1% (balloon angio‐plasty: 75%, bare metal stent 40%, DES: 58.3%). Even in the era of DES, clinical results favored CABG. The difference in clinical results is due to the sustainability of successful revascularization.

Increased Graft Occlusion or String Sign in Composite Arterial Grafting for Mildly Stenosed Target Vessels

BACKGROUND Composite grafting is a useful technique that avoids the need for aortic manipulation and enables a wide range of target vessels to be revascularized, effectively using the limited arterial grafts available. However, it has not been clarified whether composite grafting can achieve angiographic outcomes equivalent to those obtained with individual grafting for specific target vessels. METHODS We retrospectively reviewed 830 distal arterial graft anastomoses in 256 patients who underwent off-pump coronary artery bypass surgery and also underwent 1-year follow-up coronary angiograms. Four hundred and ten anastomoses using a composite grafting technique were compared with 420 anastomoses using individual grafting. RESULTS In target vessels with mild stenosis, the incidence of graft occlusion or string sign was significantly higher in composite internal thoracic arteries (ITA) than in individual ITA grafts (composite 20.3% versus individual 7.3%; p = 0.018) and showed a higher tendency in composite radial arteries (RA) than in individual RA grafts (59.3% versus 36.4%, p = 0.09). In contrast, the incidence was similar between composite and individual ITA grafts (5.7% versus 3.3%, p = 0.278) and composite and individual RA grafts (11.5% versus 29.6%, p = 0.297) in target vessels with severe stenosis. CONCLUSIONS The angiographic outcomes of composite grafts were closely related to the severity of stenosis of the target coronary artery. In target vessels with mild stenosis, composite grafting resulted in a higher incidence of graft occlusion or string sign than individual grafting did.

Graft Selection and One-Year Patency Rates in Patients Undergoing Coronary Artery Bypass Grafting

BACKGROUND The aim of this study was to assess the angiographic patency rates of grafts used for coronary artery bypass surgery. METHODS We reviewed the records of 930 patients who underwent isolated coronary artery bypass grafting between September 2004 and June 2009. Of these patients, 95.1% underwent off-pump coronary artery bypass grafting. Early and 1-year angiographic patency rates of grafts were assessed. RESULTS Mean anastomoses per patient were 4.0 +/- 1.3. Operative mortality was 0.5%. Stroke occurred in 2.2% of patients, and 1.3% had mediastinitis. Early and 1-year patency rate of total grafts was 97.4% and 87.5%, respectively. One-year patency rate of the left internal thoracic artery, right internal thoracic artery, radial artery, gastroepiploic artery, and saphenous vein graft was 96.1%, 92.0%, 69.5%, 81.4%, and 82.6%, respectively. One-year patency rates of in situ and free right internal artery graft were not significantly different (p = 0.13). One-year patency rate of the radial artery was significantly worse than that of the free right internal thoracic artery graft (p < 0.01) and saphenous vein graft (p < 0.01). CONCLUSIONS Multiple coronary arterial revascularizations in various combinations of grafts were clinically safe and effective for isolated coronary artery bypass surgery. Bilateral internal thoracic artery grafting for the left coronary artery system was the most reliable strategy as shown by angiographic patency rates.

Outcomes of total arch replacement with stepwise distal anastomosis technique and modified perfusion strategy

OBJECTIVE Total arch replacement has been reported to present high morbidity and mortality. We have introduced a stepwise distal anastomosis technique and modified perfusion strategy, including selective antegrade cerebral perfusion, moderate hypothermia, and separate lower-body perfusion, to minimize organ ischemia and secondary morbidities. We report the operative outcomes of total arch replacement with our modified perfusion strategy. METHODS Between August 2006 and December 2008, 119 patients underwent total arch replacement with the current perfusion strategy. Of these patients, 56 (47%) underwent emergency operation for acute type A aortic dissection (n = 48) or ruptured thoracic aneurysm (n = 8). The mean age of patients was 68 years, and the mean follow-up period was 25 months. We analyzed operative mortality, morbidity, and 4-year survival of this patient group. RESULTS The mean operation, cardiopulmonary bypass, and circulatory arrest times were 313, 183, and 47 minutes, respectively. Operative mortality was 3.4%. Operative mortality of elective cases was 1.6%. The incidences of permanent neurologic deficit, paraparesis, and renal insufficiency were 5.0%, 1.7%, and 7.6%, respectively. Actuarial 4-year survival was 86.5%. CONCLUSIONS Total arch replacement with our modified perfusion strategy has demonstrated low operative mortality and morbidity.

Mechanisms of Recurrent Regurgitation After Valve Repair for Prolapsed Mitral Valve Disease

BACKGROUND We assessed mitral valve (MV) function using serial echocardiography as an indicator of the durability of MV repair. The aim of this study was to analyze the mechanisms of recurrent regurgitation after MV repair for degenerative disease. METHODS From 1991 to 2007, 736 patients had valve repair for mitral regurgitation caused by leaflet prolapse: 346 patients had posterior and 390 had anterior leaflet prolapse. The mean age was 54.6±14.6 years, with 495 males. The durability and mechanisms of recurrent regurgitation were evaluated by the findings of echocardiography and reoperation. Follow-up and late echocardiography averaged 5.7±3.9 and 5.1±3.6 years, respectively. RESULTS Survival was 91.9%±1.5% at 10 years. Freedom from reoperation and moderate or severe regurgitation at 10 years were 91.2%±1.7% and 84.5%±2.1%, respectively. Reoperations were performed for recurrent regurgitation in 29 patients, hemolysis in 5, and endocarditis in 1. Based on the findings of reoperation, the mechanisms of repair failure were procedure related in 9 (25.7%), valve related in 25 (71.4%), and unknown in 1. Late echocardiography revealed none to trivial regurgitation in 511 patients, mild in 153, moderate in 26, and severe in 40. Anterior leaflet prolapse, preoperative atrial fibrillation, and no use of annuloplasty ring were independent predictors of recurrent regurgitation. The main causes of moderate or severe regurgitation were leaflet thickening in 34 patients, leaflet prolapse in 20, dehiscence in 10, and unknown in 2. CONCLUSIONS The main mechanism of recurrent regurgitation after MV repair is progressive degeneration that is characterized by leaflet thickening and prolapse, especially in patients with anterior leaflet prolapse.

Angiographic outcomes of right internal thoracic artery grafts in situ or as free grafts in coronary artery bypass grafting

OBJECTIVE We sought to compare early and 1-year angiographic results of various coronary artery bypass grafting configurations with the right internal thoracic artery in combination with the left internal thoracic artery. METHODS We reviewed the records of 705 patients who underwent bilateral internal thoracic artery grafting between September 2004 and November 2008. The right internal thoracic artery was used as an in situ graft in 547 patients and as a free graft in 158 patients. We compared operative and postoperative variables and early and 1-year angiographic patency rates of the right internal thoracic artery between the groups. RESULTS The operative mortality and incidence of postoperative complications were not significantly different between groups. The overall patency rates of the right internal thoracic artery were 98.8% at early angiography and 94.3% at 1-year postoperative follow-up. There were no significant differences in patency rate between in situ and free right internal thoracic artery grafts (98.6% vs 99.3% early and 95.3% vs 89.8% at 1 year). The best patency rate of the right internal thoracic artery was achieved with in situ grafting to the left anterior descending system (99.4% early and 98.5% at 1 year). CONCLUSIONS Patency rates of in situ and free right internal thoracic artery grafts were similar in early and 1-year angiographic studies. Among various configurations, the best patency of the right internal thoracic artery was obtained with in situ grafting to the left anterior descending coronary artery.

Efficacy and pitfalls of transapical cannulation for the repair of acute type A aortic dissection.

BACKGROUND Selection of a cannulation site for the repair of acute type A aortic dissection remains controversial. Several cannulation sites have been introduced, but each is associated with a risk of adverse complications. Transapical cannulation is a simple procedure to restore antegrade blood flow during ECC. However the efficacy of this procedure is unknown. METHODS Among 400 patients undergoing surgical repair of acute type A dissection at Sakakibara Heart Institute between 2003 and 2010, transapical cannulation was performed in 52 patients, and these patients were included in this study. Transapical cannulation was selected as the initial cannulation site in 44 patients and as conversion from femoral cannulation in 8 patients. RESULTS There were 4 in-hospital mortalities (mortality rate, 7.7%) and 5 patients had strokes (stroke rate, 9.6%). Transapical cannulation was successful in 47 patients (90.4%). Conversion of the cannulation site was necessary in 5 patients: Malperfusion on initiation of ECC was observed in 4 patients and emergence of aortic regurgitation was observed in 1 patient. The cannula was moved to another artery for correction in these patients. There was no mortality in patients undergoing conversion of the cannulation site. CONCLUSIONS Transapical cannulation is considered an effective option for the repair of acute type A aortic dissection. Transapical cannulation cannot eliminate the risk of intraoperative malperfusion, and therefore careful assessment with intraoperative monitoring is necessary.

Long-Term Outcome of Mitral Valve Repair for Infective Endocarditis

BACKGROUND In patients with mitral endocarditis, reconstruction of the damaged mitral valve (MV) is still challenging, and its durability remains unknown. We evaluated the long-term outcomes of MV repair for mitral regurgitation (MR) in patients with infective endocarditis. METHODS From 1991 to 2006, 633 patients had MV repair for MR caused by leaflet prolapse: 78 had endocarditis (active in 14, healed in 64) and 555 had degenerative disease. Durability was assessed by reoperation and recurrent MR. RESULTS The overall hospital mortality rate was 1.0% (endocarditis 0% vs degenerative 1.1%; p = 0.99). The 10-year survival and freedom from reoperation were 91.1 +/- 1.6% and 92.2 +/- 1.7%, respectively, with no differences between endocarditis and degenerative disease. Older age, New York Heart Association class III or IV, impaired ventricular function, and no use of annuloplasty were independent predictors of all-cause death. Freedom from moderate or severe MR was 99.8 +/- 0.2% at 2 weeks, 91.9 +/- 1.5% at 5 years, and 83.3 +/- 2.3% at 10 years, for all patients and did not differ between groups at 10 years (p = 0.388). Anterior leaflet prolapse, preoperative atrial fibrillation, and no annuloplasty were independent predictors of recurrent MR. In endocarditis patients, recurrent MR was mainly caused by leaflet thickening and calcification, but not by recurrence of endocarditis. CONCLUSIONS MV repair for endocarditis is associated with low operative mortality and morbidity, and its long-term durability is comparable with that of repair for degenerative disease. This study suggests that a degenerative process causes late failure after MV repair for endocarditis.