Early and Long-Term Outcomes of Transcatheter Aortic Valve Replacement for Selected Nonagenarians in Japan.

BACKGROUND: Transcatheter aortic valve implantation (TAVI) is increasingly being performed in very elderly patients, although its efficacy and validity remain unclear. This study evaluated real-world TAVI outcomes in Japanese nonagenarians with severe aortic stenosis.Methods and Results: This single-center study retrospectively assessed the early and long-term clinical outcomes of TAVI in nonagenarians (n=35) and in patients aged <90 years (group Y; n=171). There were no in-hospital deaths in either group. The device success rate and early safety were comparable between the 2 groups. The 5-year rates of freedom from cardiac events and deaths were equivalent in both groups. The cumulative survival rate at 5 years was non-significantly lower in nonagenarians (32.6% in nonagenarians vs. 57.5% in patients aged <90 years, P=0.49). There were no differences in the 5-year survival between nonagenarians after TAVI and the sex- and age-matched populations (P=0.18). The Cox regression model revealed that lower hemoglobin levels were associated with all-cause mortality (P=0.02), and age ≥90 years was not associated with all-cause mortality. CONCLUSIONS: The early and long-term clinical outcomes of TAVI for selected Japanese nonagenarians were comparable to those in patients aged <90 years. Nonagenarians who underwent TAVI achieved an acceptable prognosis compared to the sex- and age-matched population; thus, TAVI appears to be effective for treating aortic stenosis in Japanese nonagenarians.

Intimal-protected adventitial inversion technique accelerates the obliteration of a patent false lumen.

BACKGROUND AND AIMS: The optimal procedure for reconstructing the dissected aortic stump for acute type A dissection remains controversial. We routinely used the intimal-protected adventitial inversion technique (iPAIT), a modified adventitial inversion technique, to protect the fragile intima by inserting a graft and assessed the safety and efficacy of this technique. METHODS: Between August 2008 and April 2020, 146 consecutive patients with acute type A dissections underwent thoracic aortic surgery in our hospital. Extended total aortic arch replacement was performed in 119 patients (81.5%). Sixty-nine patients underwent treatment for distal aortic anastomosis with the iPAIT. To compare the iPAIT to a historical control, we assessed 69 iPAIT patients and 25 patients who underwent total arch replacement using gelatin-resorcinol-formaldehyde (GRF) glue. RESULTS: Hospital mortality was 2.9% in the iPAIT group and 8.0% in the GRF group. Perioperative characteristics were similar between the two groups. However, postoperative computed tomography revealed that the obliteration rate was significantly higher in the iPAIT group (60/66, 90.9%) than in the GRF group (15/23, 65.2%) (p = .01), not including the patients who had died or developed severe renal dysfunction. The 8-year aortic event-free survival rate in the iPAIT group (81.3%) was significantly higher than that in the GRF group (47.4%). CONCLUSIONS: The use of this technique for acute type A dissections resulted in a low mortality rate and demonstrated promising midterm survival and may accelerate the obliteration of a patent false lumen and prevent late aortic events.

Validity of direct bilateral axillary arterial cannulation in emergency surgery for acute type A aortic dissection.

BACKGROUND AND AIM OF THE STUDY: To assess the validity and long-term outcomes of direct bilateral axillary arterial cannulation for acute type A aortic dissection. METHODS: Between 2003 and 2020, 208 consecutive patients with acute type A aortic dissection underwent emergency surgical repair. Cardiopulmonary bypass was attempted to establish direct bilateral axillary arterial cannulation and bicaval drainage. Antegrade selective cerebral perfusion was established by axillary perfusion and direct cannulation of the left common carotid artery. RESULTS: Ascending aortic, partial arch, and extended total aortic arch replacement were performed in 50 (24.0%), 7 (3.4%), and 151 (72.6%) patients, respectively. Aortic root surgery and coronary artery bypass grafting were performed concomitantly in 23 and seven patients, respectively. Cardiopulmonary bypass was attempted only through bilateral axillary cannulation in all patients but was successful in 13 (6.3%) patients without bilateral axillary cannulation. No postoperative complications occurred related to this technique. There were seven hospital deaths (early mortality rate, 3.4%). Five patients had postoperative reoperation for bleeding, and nine (4.3%) were transferred to other hospitals due to postoperative permanent cerebral infarction, particularly two with arm ischemia. The 10-year survival rate of patients who underwent emergency surgical repair with this technique was 71.4%. CONCLUSIONS: Direct bilateral axillary arterial cannulation followed by selective cerebral perfusion was successful in 93.7% of patients and this may be an optimal solution for providing stable outcomes after emergency surgery for acute type A aortic dissection. However, we experienced two complications of arm ischemia, attention should be paid to potential arm ischemia.

[Subcutaneous Bronchogenic Cyst in the Anterior Chest Diagnosed before Coronary Artery Bypass Grafting:Report of a Case].

A 65-year-old woman was transported to our hospital by ambulance because of severe dyspnea. She had had a subcutaneous tumor on her anterior chest since her childhood. Coronary angiography revealed three vessel disease with significant stenosis in the left main trunk. Excision of anterior chest tumor, 70×60×50 mm in size, was performed before coronary artery bypass grafting( CABG). It was a unilocular cyst adhering to the sternum, and was composed of ciliated epitheliums, goblet cells and smooth muscle cells. Based upon the existence of smooth muscle cells, the tumor was diagnosed as bronchogenic cyst. CABG was performed through mid-sternum about two months after the tumor excision, and the postoperative course was uneventful.

Preoperative evaluation of aortic calcification by computed tomography in thoracic aortic disease.

BACKGROUND: Computed tomography (CT) is a useful tool for the identification of calcified lesions in the aorta. However, no quantitative evaluation has been established to assess the applicability of simple anastomosis preoperatively. We conducted this retrospective study to establish a reference range of maximal CT attenuation values for application of simple anastomosis. METHODS: A total of 122 consecutive patients underwent replacement of the thoracic aorta between 2007 and 2011, excluding those with acute aortic dissection. The patients were divided into two groups: those who underwent simple anastomosis (simple group: n = 105), and those who required endarterectomy before anastomosis (manipulation group: n = 17). The maximal CT attenuation values at the anastomosis site were calculated by imaging software. RESULTS: The mean maximal CT attenuation values (Hounsfield unit [HU]) was significantly higher in the manipulation group (638.1 ± 269.5 [166-1304]) than in the simple group (94.7 ± 171.5 [0-790]; p < .0001). The maximal CT attenuation values enabled us to predict the simple anastomosis with the area under the receiver operating characteristic curve of 0.96 (p < .0001). The cut-off value was 325 HU (sensitivity 94.1%, specificity 81.7%). The 10-year survival rate was significantly lower in the manipulation group (11.8%) than in the simple group (43.2%). In the multivariate analysis, age (hazard ratio [HR]: 1.073), hypertension (HR: 2.382), and maximal CT attenuation values (HR: 1.001) were independently associated with long-term mortality. CONCLUSIONS: Preoperative evaluation of the maximal CT attenuation values is a useful tool in predicting whether simple anastomosis is applicable or not. Maximal CT attenuation values is a risk factor for long-term mortality.

Role of Computed Tomography in Planning the Appropriate X-Ray Gantry for Quantitative Aortography of Post-transcatheter Aortic Valve Implantation Regurgitation.

BACKGROUND: The clinical robustness of contrast-videodensitometric (VD) assessment of aortic regurgitation (AR) after transcatheter aortic valve implantation (TAVI) has been demonstrated. Correct acquisition of aortic root angiography for VD assessment, however, is hampered by the opacified descending aorta and by individual anatomic peculiarities. The aim of this study was to use preprocedural multi-slice computed tomography (MSCT) to optimize the angiographic projection in order to improve the feasibility of VD assessment.Methods and Results:In 92 consecutive patients, post-TAVI AR (i.e., left ventricular outflow tract [LVOT] AR) was assessed on aortic root angiograms using VD software. The patients were divided into 2 groups: The first group of 54 patients was investigated prior to the introduction of the standardized acquisition protocol; the second group of 38 consecutive patients after implementation of the standardized acquisition protocol, involving MSCT planning of the optimal angiographic projection. Optimal projection planning has dramatically improved the feasibility of VD assessment from 57.4% prior to the standardized acquisition protocol, to 100% after the protocol was implemented. In 69 analyzable aortograms (69/92; 75%), LVOT-AR ranged from 3% to 28% with a median of 12%. Inter-observer agreement was high (mean difference±SD, 1±2%), and the 2 observers' measurements were highly correlated (r=0.94, P<0.0001). CONCLUSIONS: Introduction of computed tomography-guided angiographic image acquisition has significantly improved the analyzability of the angiographic VD assessment of post-TAVI AR.

Inter-Technique Consistency and Prognostic Value of Intra-Procedural Angiographic and Echocardiographic Assessment of Aortic Regurgitation After Transcatheter Aortic Valve Implantation.

BACKGROUND: We investigated the relationship between intraprocedural angiographic and echocardiographic AR severity after TAVI, and the clinical robustness of angiographic assessment. Methods and Results: In 74 consecutive patients, the echocardiographic circumferential extent (CE) of the paravalvular regurgitant jet was retrospectively measured and graded based on the VARC-2 cut-points; and angiographic post-TAVI AR was retrospectively quantified using contrast videodensitometry (VD) software that calculates the ratio of the contrast time-density integral in the LV outflow tract to that in the ascending aorta (LVOT-AR). Seventy-four echocardiograms immediately after TAVI were analyzable, while 51 aortograms were analyzable for VD. These 51 echocardiograms and VD were evaluated. Median LVOT-AR across the echocardiographic AR grades was as follows: none-trace, 0.07 (IQR, 0.05-0.11); mild, 0.12 (IQR, 0.09-0.15); and moderate, 0.17 (IQR, 0.15-0.22; P<0.05 for none-trace vs. mild, and mild vs. moderate). LVOT-AR strongly correlated with %CE (r=0.72, P<0.0001). At 1 year, the rate of the composite end-point of all-cause death or HF re-hospitalization was significantly higher in >mild AR patients compared with no-mild AR on intra-procedural echocardiography (41.5% vs. 12.4%, P=0.03) as well as in patients with LVOT-AR >0.17 compared with LVOT-AR ≤0.17 (59.5% vs. 16.6%, P=0.03). CONCLUSIONS: VD (LVOT-AR) has good intra-procedural inter-technique consistency and clinical robustness. Greater than mild post-TAVI AR, but not mild post-TAVI AR, is associated with late mortality.

Age-related increase in Wnt inhibitor causes a senescence-like phenotype in human cardiac stem cells.

Aging of cardiac stem/progenitor cells (CSCs) impairs heart regeneration and leads to unsatisfactory outcomes of cell-based therapies. As the precise mechanisms underlying CSC aging remain unclear, the use of therapeutic strategies for elderly patients with heart failure is severely delayed. In this study, we used human cardiosphere-derived cells (CDCs), a subtype of CSC found in the postnatal heart, to identify secreted factor(s) associated with CSC aging. Human CDCs were isolated from heart failure patients of various ages (2-83 years old). Gene expression of key soluble factors was compared between CDCs derived from young and elderly patients. Among these factors, SFRP1, a gene encoding a Wnt antagonist, was significantly up-regulated in CDCs from elderly patients (≥65 years old). sFRP1 levels was increased significantly also in CDCs, whose senescent phenotype was induced by anti-cancer drug treatment. These results suggest the participation of sFRP1 in CSC aging. We show that the administration of recombinant sFRP1 induced cellular senescence in CDCs derived from young patients, as indicated by increased levels of markers such as p16, and a senescence-associated secretory phenotype. In addition, co-administration of recombinant sFRP1 could abrogate the accelerated CDC proliferation induced by Wnt3A. Taken together, our results suggest that canonical Wnt signaling and its antagonist, sFRP1, regulate proliferation of human CSCs. Furthermore, excess sFRP1 in elderly patients causes CSC aging.

[Aortic Arch-descending Aorta Bypass for Intraoperative Lower Body Malperfusion during Chronic Type A Aortic Dissection Repair].

We present a case of intraoperative lower body malperfusion in a 55-year-old woman who was undergoing total aortic arch replacement (TAR) for chronic type A aortic dissection. We planned 2-staged operation that consisted of total aortic arch replacement using the elephant trunk technique and thoracic endovascular aneurysm repair. During the 1st surgery, hemodynamic findings after TAR indicated lower body malperfusion, with the blood pressure of the upper body of 127/46 (68) mmHg and that of the lower body of 71/46 (51) mmHg. Transesophageal echocardiography showed narrowing of the true lumen and expansion of the false lumen of the proximal descending aorta. We performed aortic arch-descending aorta bypass using the branch for arterial return of the prosthetic arch graft. After the bypass procedure, lower body malperfusion improved. The postoperative course was uneventful. Extraanatomical aortic arch-descending aorta bypass may be an option for improving intraoperative malperfusion of the lower body due to true lumen narrowing.

[Radical nephrectomy and caval tumor thrombectomy with cardiopulmonary bypass combined with right anterior minithoracotomy;report of a case].

Renal cell carcinoma is a tumor with a distinct feature that it can invade the renal vein and grow intravascularly extending to the inferior vena cava (IVC). We herein report a case of a 71-year-old female who presented with a neoplasm that involved the right kidney and an intra-IVC tumor thrombus. We performed radical nephrectomy and tumor thrombectomy under cardiopulmonary bypass through a right anterior mini thoracotomy. The patient was discharged on the 13th day after the surgery without any complication, and is currently in good health at 7 months after the operation.

Important role of the angiotensin II pathway in producing matrix metalloproteinase-9 in human thoracic aortic aneurysms.

BACKGROUND: The precise pathologic mechanisms underlying human thoracic aortic aneurysms (TAAs) remain uncertain, except that matrix metalloproteinase-9 (MMP-9) is considered a key enzyme for the degradation of extracellular matrix in aneurysm walls. The aim of this study was to elucidate the significance of the angiotensin II (AngII) pathway to MMP-9 production in human TAA walls. METHODS AND RESULTS: We examined the activation of Smad2, a common downstream molecule of AngII and transforming growth factor ß (TGF-ß) pathways, and the expression of MMP-9 in human nonsyndromic TAA walls. We observed significant increases in Smad2 activation and MMP-9 expression, associated with disruption of elastic lamellae. Using human TAA walls in ex vivo culture, we investigated whether AngII and/or TGF-ß pathways are essential for MMP-9 production. Unexpectedly, TGF-ß receptor inhibitor had no effect on MMP-9 production. We used PD98059, an inhibitor of extracellular signal-regulated kinase (ERK) activation, and demonstrated that PD98059 dramatically reduced MMP-9 production with attenuation of Smad2 activation. Moreover, exogenous AngII resulted in increases in Smad2 activation and MMP-9 production, in an ERK-dependent manner. CONCLUSION: Our findings indicate that the AngII/ERK pathway has an important role in the production of MMP-9 in human nonsyndromic TAA walls.

[Apico-aortic valved conduit for aortic stenosis in patients who could not tolerate median sternotomy].

UNLABELLED: This report presents 3 cases treated with an apico-aortic valved conduit. Cases 1, 2:A 67-year-old female patient and a 60-year-old male patient what had undergone coronary artery bypass grafting were admitted to our hospital for severe aortic stenosis. Computed tomography showed a severe calcified ascending aorta, and coronary angiography revealed patent bypass graft. Case 3:A 71-year-old male patient that had esophagectomy with retrosternal colonic interposition for esophagus cancer after distal gastrectomy. In addition, he had experienced anterior mediastinal drainagic therapy for anastomotic leak. All 3 patients were treated by implantation of an apico-aortic valved conduit. Operation:This procedure was performed through the 5th intercostal space under a beating heart with cardiopulmonary bypass. RESULT: Postoperative courses were uneventful. All patients are still alive without procedure-related events. CONCLUSION: This surgical procedure can be an effective alternative when conventional aortic valve replacement cannot be performed for aortic stenosis patients.

[Video-assisted thoracoscopic implantation of left ventricular pacing lead;usefulness of CARTO system;report of a case].

A 70-year-old man, with a history of broad anterior myocardial infarction and repeated several hospitalizations due to heart failure, was referred to our institution for cardiac resynchronization therapy. However, as intravenous implantation of the left ventricular pacemaker lead was not possible, the patient underwent video-assisted thoracoscopic (VAT) implantation. We noted broad myocardial scarring and patent grafts, along with previously bypassed left internal thoracic artery( LITA)-left anterior descending artery (LAD) and right internal thoracic artery (RITA)-D1;thus, the area suitable for implantation of the left ventricule (LV) pacemaker was believed to be restricted. Therefore, we decided to determine the viable myocardial area by using CARTO system and identify the appropriate access port positions for the subsequent VAT surgery. After the LV pacemaker lead was implanted, the recorded pacing threshold was found to be <1.2 V at 0.5 ms. Thus, the CARTO system might be useful to preoperatively identify an area suitable for surgical implantation of a LV pacemaker lead in patients with ischemic cardiomyopathy.

Early and Late Surgical Outcomes after Geometrical Infarct Exclusion for Post-Infarct Ventricular Septal Perforation.

PURPOSE: Ventricular septal perforation (VSP) is a critical complication of acute myocardial infarction. Various surgical procedures for it have been developed; however, surgical outcomes remain unsatisfactory. In 2010, we introduced geometrical infarct exclusion (GIE) as a modification of the Komeda-David technique. This retrospective study compared the surgical outcomes of our geometric infarct exclusion technique to those of other surgical procedures. METHODS: This study included 38 patients who underwent surgery for VSP. They were divided into patients who underwent GIE (GIE group; n = 17) and those who underwent other procedures (non-GIE group; n = 21). The clinical outcomes of the two groups were compared. RESULTS: Operation, cardiopulmonary bypass, and cardiac arrest times in the GIE group were significantly longer than those in the non-GIE group (p <0.001). A residual shunt was observed in one patient (5.8%) in the GIE group and eight (38.0%) in the non-GIE group (p = 0.026). No patients in the GIE group required a reoperation for the residual shut, while two patients required it in the non-GIE group (p = 0.492). Operative mortality was insignificantly different between the two groups. CONCLUSION: Geometric infarct exclusion has a longer procedural time than does other surgical procedures but can reduce the rates of residual shunts and reoperations.

[Surgical therapy for ischemic cardiomyopathy].

BACKGROUND: Surgical ventricular restoration (SVR) is considered as an effective surgical procedure for patients with ischemic myocardiopathy( ICM). However" surgical treatment for ischemic heart failure (STICH)" trial concluded that adding SVR to coronary artery bypass grafting (CABG) did not relieve symptoms and failed to lower death rate or cardiac rehospitalization as compared with CABG alone. AIM: The aim of this study was to investigate the efficacy of CABG with SVR for ICM. METHODS AND RESULTS: We retrospectively studied 24 patients who had undergone CABG with or with out SVR for ICM from October 1992 to June 2008. In CABG with SVR group, cardiac symptoms were relieved and the left ventricular end-systolic volume index (LVESVI) was reduced from the baseline significantly. However cardiac symptoms were relieved only in CABG-S [left ventricular end-diastolic dimension (LVDd)<60 mm] group, and not in CABG-L (LVDd≥60 mm) group. LVESVI was not reduced in CABG without SVR group. CONCLUSION: SVR contributed to relieving the symptoms, and improving the left ventricular function and the long-term survival of patients with especially dilated ICM, which could not be achieved by CABG alone.

Feasibility of open chest management with modified negative pressure wound therapy immediately after cardiac surgery.

OBJECTIVES: To evaluate the feasibility of open chest management with our modified negative pressure wound therapy immediately after cardiac surgery as a therapy for atypical tamponade. METHODS: Open chest with modified negative pressure wound therapy was performed immediately after cardiac surgery. The surface of the heart and the vessels were covered with non-adherent siliconized gauze. The sternal halves were stented using edge-cut disposable syringes to maintain a larger mediastinal cavity. Approximately 45 mm of distance was kept between the sternal edges. A trimmed sterile polyvinyl foam sponge was inserted into the mediastinum, the entire wound was sealed and negative pressure (-50 to -75 mmHg) was applied using a suction generator. Delayed chest closure was performed in a standard manner once the haemodynamic status was stabilizsed. RESULTS: The mortality rate was 3/15 (20%) patients. Deep sternal wound infection occurred in 1/15 (6.7%) patients. Five patients were extubated during the open chest management. Sternal closure was delayed for median of 3 days after the initial surgery. There was no incidence of bleeding complications or need for additional haemostatic procedures. CONCLUSIONS: Negative pressure wound therapy performed immediately after cardiac surgery was feasible in our small number of patients. CLINICAL REGISTRATION NUMBER: Study ID: 2020-149.

Impact of the no-touch harvesting technique on the vessel diameter of saphenous vein grafts for coronary artery bypass grafting.

Objectives: To explore the impact of the no-touch harvesting technique on the vessel diameter of saphenous vein grafts. Methods: This retrospective, single-center study enrolled 166 patients who underwent isolated coronary artery bypass grafting using saphenous vein grafts. Saphenous vein grafts were harvested conventionally in 83 patients (conventional group) and using the no-touch technique in 83 patients (no-touch group). We analyzed graft patency and the vessel diameters of saphenous vein grafts in the pre- and postoperative states. The diameter mismatch between the saphenous vein grafts and the coronary artery at the anastomotic site was also measured; preoperative diameter was measured using ultrasound imaging, and the postoperative diameter was measured using electrocardiogram-gated enhanced computed tomography. Results: A total of 135 saphenous vein grafts (66 and 69 grafts in the conventional and no-touch groups, respectively) were evaluated for postoperative patency. Graft patency was equivalent in the 2 groups (conventional, 96.9% vs no-touch, 100%; P = .24). A detailed evaluation was performed in 109 saphenous vein grafts (52 and 57 grafts in the conventional and no-touch groups, respectively). Saphenous vein graft diameter was significantly distended in the conventional group (preoperative, 2.6 ± 0.7 mm vs postoperative, 3.4 ± 0.5 mm; P < .0001). However, saphenous vein graft diameter did not change in the no-touch group (preoperative, 2.9 ± 0.4 mm vs postoperative 2.8 ± 0.4 mm, P = .33). The diameter mismatch was significantly smaller in the no-touch group (conventional 1.4 ± 0.6 mm vs no-touch 1.0 ± 0.4 mm, P < .0001). Conclusions: The no-touch technique avoids the expansion of graft diameter and diameter mismatch between the saphenous vein grafts and coronary artery.

Fate of dissected arch vessels by adventitial inversion technique for acute type A aortic dissection repair.

OBJECTIVES: The adventitial inversion technique is used widely for aortic reconstruction for acute type A aortic dissection, as it easily controls the bleeding at anastomotic sites and closes the patent false lumen. However, this technique for arch vessel reconstruction has not been previously reported. Therefore, we applied the adventitial inversion technique for dissected arch vessel reconstruction to close the patent false lumen. METHODS: Among 57 consecutive patients who underwent emergency surgical treatment for acute type A aortic dissection from July 2006 to July 2012, the adventitial inversion technique for the dissected arch vessels was performed in 26 patients (42 arch vessel stumps). The patency and morphologic change of the false lumen of the arch vessels were evaluated using contrast-enhanced computed tomography. RESULTS: Overall, 2 hospital deaths were recorded, and the hospital mortality rate was 4%. No postoperative cerebral strokes and reoperations due to bleeding occurred. Follow-up by contrast-enhanced computed tomography was completed in 24 patients (37 stumps) with a mean duration of 99 ± 35 months. The postoperative closure rate of the false lumen after adventitial inversion was 86%, which was higher than when adventitial inversion was not used. No adverse events including stroke occurred during follow-up period. CONCLUSIONS: This technique facilitates the closure of the false lumen of dissected arch vessels and might improve clinical outcomes.

Perivascular Adipose Tissue Is a Major Source of Nitric Oxide in Saphenous Vein Grafts Harvested via the No-Touch Technique.

Background Saphenous vein grafts (SVGs) are broadly used in coronary artery bypass grafting despite their inferior patency compared with arterial grafts. Recently, the no-touch technique (NT), in which an SVG is harvested with a pedicle of perivascular adipose tissue (PVAT) without conduit distension, was shown to improve long-term patency compared with conventional preparation (CV), wherein outer tissue is removed with distension. The NT was also reportedly associated with reduced atherosclerosis. Although endothelial damage provoked by conventional distension may underlie poor patency when CV is performed, the precise mechanisms underlying the salutary effects of the NT have been unclear. Methods and Results Residual SVGs prepared with CV (CV-SVGs) or NT (NT-SVGs) were obtained during coronary artery bypass grafting. Nitric oxide (NO2-/NO3- (NOx)) levels after 24 hours of tissue culture were quantified. The protein expression and localization were analyzed. The isometric force of SVG strips was measured. NT-SVGs showed superior NOx production to CV-SVGs. PVAT generated the majority of NOx in NT-SVGs. PVAT highly expressed arginosuccinate synthase 1, a rate-limiting enzyme in the molecular circuit for NO synthesis, thereby continuously providing the substrate for NO. A substantial level of endothelial NO synthase was also expressed in PVAT. Pharmacological inhibition of arginosuccinate synthase 1 or endothelial NO synthase significantly suppressed the NOx production in NT-SVGs. PVAT induced vasorelaxation through NO production, even in the endothelium-denuded SVG strips. Conclusions Preserving PVAT was predominantly involved in the superior NOx production in NT-SVGs. Since NO plays crucial roles in suppressing atherosclerosis, this mechanism may greatly contribute to the excellent patency in NT-SVGs.