Comparison of bare and nonbare stent grafts during thoracic endovascular aneurysm repair of the aortic arch.

OBJECTIVE: We compared the outcomes of patients treated with nonbare stents (NBS) and proximal bare stents (PBS) endografts with a proximal landing zone in the aortic arch during thoracic endovascular aortic repair (TEVAR). METHODS: We conducted a retrospective cohort, observational, multicenter study that included 361 consecutive TEVAR procedures undertaken between November 2005 and December 2021. TEVAR patients with both BS and NBS Relay stent graft configurations with proximal landing in zones 1, 2, or 3 were enrolled. Preoperative anamnestic and morphological data, clinical outcomes, and aortic modifications 30 days after surgery and at the latest follow-up available were collected. The primary outcome was freedom from proximal endoleak (type IA) comparing the two configurations. Total and detailed endoleak rates, clinical and technical success, intraoperative additional maneuvers, major adverse events, and reinterventions were secondary outcomes. RESULTS: The median follow-up was 4.9 (interquartile range, 2.0-8.1) years. No statistically significant difference between NBS and PBS patients concerning 30-day major adverse events, retrograde aortic dissection, disabling stroke, or late type IA endoleak (10.8% vs 7.8%; P = .597). Aneurysmal disease (P = .026), PLZ diameter of >34 mm (P = .026), aortic tortuosity index of >1.4 (P = .008), type III aortic arch (P = .068), and PLZ thrombus (P = .014) identified as risk factors by univariate Cox regression analysis. PLZ thrombus was the only type IA endoleak risk factor at multivariate Cox regression (P = .016). CONCLUSIONS: We found no statistically significant difference in freedom from type IA endoleak, retrograde dissection, or disabling stroke observed between the NBS and the BS configuration of the Relay endograft. Proximal landing zone thrombotic apposition was a prominent risk factor for type IA endoleak after TEVAR.

Carbon Monoxide Suppresses Neointima Formation in Transplant Arteriosclerosis by Inhibiting Vascular Progenitor Cell Differentiation.

[Figure: see text].

Reoperation after Implanting a Triple-Branched Stent Graft: Case Report.

Acute type A aortic dissection (ATAAD) is an aortic catastrophe with high mortality, requiring immediate surgical intervention. Recently, placement of a triple-branch stent graft has emerged as an effective technique for total arch reconstruction. Indications for this approach, however, are limited by various complications, such as endoleak, stent graft migration or kinking, and spontaneous thrombosis. Here, we report a case of Marfan syndrome in which the patient underwent a reoperation owing to frame fractures (or degradation of graft material) in a triple-branched stent graft implanted 5 years earlier.

Postpartum Stanford type B aortic dissection in a woman with Loeys-Dietz syndrome who underwent a prophylactic aortic root replacement before conception: A case report.

OBJECTIVE: Loeys-Dietz syndrome (LDS) is associated with a higher risk of aortic dissections (ADs) during pregnancy and postpartum. However, there is limited evidence about the perinatal management of LDS patients who have undergone prophylactic aortic root replacements (ARRs) before conception. CASE REPORT: We present the case of a 28-year-old nulliparous pregnant woman with LDS with a pathogenic variant within exon 5 of TGFBR2 (c.1379G > T, p.[Arg460Leu]), who underwent an ARR at 20 years of age. Cardiac echocardiography did not show any significant changes in the aorta during pregnancy, and her blood pressure remained normal. She had a cesarean section at 37 weeks of gestation. She developed an acute Stanford type B AD extending from the aortic arch to the infrarenal aorta 8 days postpartum and underwent a total arch replacement. CONCLUSION: This case report suggests that patients with LDS after prophylactic ARRs still possess a risk for Stanford type B ADs.

Dipeptidyl Peptidase-4 Inhibitor Decreases Allograft Vasculopathy Via Regulating the Functions of Endothelial Progenitor Cells in Normoglycemic Rats.

PURPOSE: Chronic rejection induces the occurrence of orthotopic allograft transplantation (OAT) vasculopathy, which results in failure of the donor organ. Numerous studies have demonstrated that in addition to regulating blood sugar homeostasis, dipeptidyl peptidase-4 (DPP-4) inhibitors can also provide efficacious therapeutic and protective effects against cardiovascular diseases. However, their effects on OAT-induced vasculopathy remain unknown. Thus, the aim of this study was to investigate the direct effects of sitagliptin on OAT vasculopathy in vivo and in vitro. METHODS: The PVG/Seac rat thoracic aorta graft to ACI/NKyo rat abdominal aorta model was used to explore the effects of sitagliptin on vasculopathy. Human endothelial progenitor cells (EPCs) were used to investigate the possible underlying mechanisms. RESULTS: We demonstrated that sitagliptin decreases vasculopathy in OAT ACI/NKyo rats. Treatment with sitagliptin decreased BNP and HMGB1 levels, increased GLP-1 activity and stromal cell-derived factor 1α (SDF-1α) expression, elevated the number of circulating EPCs, and improved the differentiation possibility of mononuclear cells to EPCs ex vivo. However, in vitro studies showed that recombinant B-type natriuretic peptide (BNP) and high mobility group box 1 (HMGB1) impaired EPC function, whereas these phenomena were reversed by glucagon-like peptide 1 (GLP-1) receptor agonist treatment. CONCLUSIONS: We suggest that the mechanisms underlying sitagliptin-mediated inhibition of OAT vasculopathy probably occur through a direct increase in GLP-1 activity. In addition to the GLP-1-dependent pathway, sitagliptin may regulate SDF-1α levels and EPC function to reduce OAT-induced vascular injury. This study may provide new prevention and treatment strategies for DPP-4 inhibitors in chronic rejection-induced vasculopathy.

Remote ALCAPA Repair-Total Arterial Reconstruction Using Free Aortic Graft Technique.

A late presenting anomalous left coronary artery from pulmonary artery (ALCAPA) with remote origin may be associated with several technical caveats due to distance for coronary transfer and inadequate autologous tissues for reconstruction. A technique using full circumferential aortic wall as a free graft that is sutured as a posterior hood on an anterior pulmonary arterial flap is used to achieve reconstruction of a neo-left coronary that is tension free, with laminar flow and without the use of any prosthetic material. The technique with potential modifications described could potentially be applied to any variant of ALCAPA to achieve total arterial reconstruction to yield an optimal long-term outcome.

The strategy of cardiopulmonary bypass for total aortic arch replacement and the frozen elephant trunk technique with aortic balloon occlusion.

OBJECTIVE: To investigate the use of the aortic balloon occlusion technique to assist total aortic arch replacement (TAR) with frozen elephant trunk (FET) to shorten the lower body circulatory arrest (CA) time and raise the nadir temperature during cardiopulmonary bypass. METHODS: This retrospective study reviewed consecutive patients that underwent aortic balloon occlusion to assist TAR with FET and patients that received conventional TAR with FET procedures. Preoperative characteristics, perioperative characteristics and postoperative outcomes were compared between the two groups. RESULTS: The study included130 patients treated with aortic balloon occlusion and 230 patients treated with conventional TAR with FET. The 30-day mortality rate was similar between the aortic balloon occlusion and conventional groups (4.62% versus 7.83%, respectively). Multivariate analysis showed that aortic balloon occlusion reduced the incidence of acute kidney injury, hepatic injury and red blood cell transfusion. The application of aortic balloon occlusion reduced the mean ± SD CA time from 17.24 ± 4.36 min to 6.33 ± 5.74 min, with the target nadir nasal temperature being increased from 25°C to 28°C. CONCLUSION: The aortic balloon occlusion technique achieved significant improvements in reducing complications, but this did not translate into lower 30-day mortality.

AAV-mediated TIMP-1 overexpression in aortic tissue reduces the severity of allograft vasculopathy in mice.

BACKGROUND: Allograft vasculopathy (AV) is the primary limiting factor for long-term graft survival. An increased activity of matrix metalloproteinases (MMPs) contributes to neointima formation in AV and represents a potential therapeutic target. Adeno-associated virus (AAV)-mediated gene therapy comprises a potentially benign vector model for the long-term expression of MMP antagonists. METHODS: Aortic allografts from DBA/2 mice were incubated with control buffer, AAV-enhanced green fluorescence protein (EGFP), or tissue inhibitor of metalloproteinases 1 (TIMP-1)-loaded AAV (AAV-TIMP-1) and transplanted into the infrarenal aorta of C57BL/6 mice. Cyclosporine A (10 mg/kg body weight) was administered daily. Explantation as well as histomorphometric and immunohistochemical evaluation was performed after 30 days. Matrix metalloproteinase (MMP) activity was visualized by gelatin in situ zymography. RESULTS: Intima-to-media area ratio and neointima formation were significantly reduced in the AAV-TIMP-1 treatment group compared with those in the control group (by 40%; p < 0.001) and the AAV-EGFP group (by 38.2%; p < 0.001). TIMP-1 overexpression positively affected several pathomechanisms for the development of AV both in vitro and in vivo as compared to that in the control groups: endothelium integrity was preserved as shown by zona occludens 1 and occludin staining; MMP9 expression and activity were significantly reduced (p = 0.01); and smooth muscle cell migration was significantly reduced as smooth muscle actin positive cells predominantly remained in the aortic media in the treatment group (p = 0.001). Moreover, macrophage infiltration was markedly reduced by 49% in the AAV-TIMP-1 group (p < 0.001). CONCLUSION: Immediate post-harvesting allograft incubation with AAV-TIMP-1 reduces neointima formation and macrophage infiltration, constituting a possible adjunct therapeutic strategy to preserve graft function after transplantation.

"Micro-Bentall" procedure.

Truncus arteriosus, an anomaly of the conotruncus, is an extremely rare congenital heart disease that affects 1.19% of all patients with congenital heart diseases.  We present a surgical technique using an 8-mm cryopreserved aortic root homograft in the aortic position and a 12-mm pulmonary valved conduit in the right position that allowed us to correct this rare congenital malformation.  The cryopreserved aortic root homograft was considered a priority option for surgical correction.  The neonatal Bentall (micro-Bentall) procedure is a surgically demanding procedure but can be performed successfully by an experienced surgeon.  If we were performing a non-salvage procedure, we would have chosen a decellularized allograft.

Murine Cervical Aortic Transplantation Model using a Modified Non-Suture Cuff Technique.

With the introduction of powerful immunosuppressive protocols, distinct advances are possible in the prevention and therapy of acute rejection episodes. However, only minor improvement in the long-term results of transplanted solid organs could be observed over the past decades. In this context, chronic allograft vasculopathy (CAV) still represents the leading cause of late organ failure in cardiac, renal and pulmonary transplantation. Thus far, the underlying pathogenesis of CAV development remains unclear, explaining why effective treatment strategies are presently missing and emphasizing a need for relevant experimental models in order to study the underlying pathophysiology leading to CAV formation. The following protocol describes a murine heterotopic cervical aortic transplantation model using a modified non-suture cuff technique. In this technique, a segment of the thoracic aorta is interpositioned in the right common carotid artery. With the use of the non-suture cuff technique, an easy to learn and reproducible model can be established, minimizing the possible heterogeneity of sutured vascular micro anastomoses.

Total endovascular aortic arch repair using chimney and periscope grafts for treatment of ruptured aortic arch pseudoaneurysm.

Aortic arch pseudoaneurysms are rare but quite fatal when ruptured. Owing to its less morbidity and mortality compared with the surgical approach, endovascular and hybrid treatment methods are increasingly preferred. In this report, we present a 58-year-old male patient who has a ruptured saccular aortic arch pseudoaneurysm treated by endovascular approach using parallel grafts.

Midterm prognosis of type B aortic dissection with and without dissecting aneurysm of descending thoracic aorta after endovascular repair.

Few studies support guidelines for the use of thoracic endovascular aortic repair (TEVAR) to address type B aortic dissection (TBAD) coexisting with descending thoracic aortic dissection and aneurysm (dTADA). This cohort study investigated midterm outcomes of TBAD with dTADA (dTADA group, n = 31) and without dTADA (non-dTADA group, n = 98) after TEVAR. Compared with the non-dTADA group, the dTADA group exhibited higher incidences of type Ia endoleak (29.0% vs. 3.1%, P < 0.001) and reintervention (16.1% vs. 5.1%, P = 0.045). The completely thrombosed rate of the thoracic false lumen was significantly lower in the dTADA group than in the non-dTADA group (45.2% vs. 80.6%, P < 0.001). Although the two groups exhibited similar mortality rates, TBAD coexisting with no regressive dTADA after TEVAR was an independent predictor of mortality (HR: 15.52, 95% CI: 1.614-149.233, P = 0.018). Moreover, the change percentages of false lumen retraction and true lumen re-expansion in the dTADA group were significantly inferior to those of the non-dTADA group at levels of 4th, 6th, 8th and 10th thoracic vertebra throughout follow-up. In conclusion, in the presence of preexisting dTADA, the failure of the dTADA to regress after TEVAR is associated with lower survival and a higher risk of reintervention.

Glomerulonephritis triggered by chronical aortic graft infection in a male with Loeys-Dietz syndrome: A case report.

RATIONALE: Glomerulonephritis triggered by a chronically infected graft is increasingly identified because of widely used implanted device. Removal of the aortic graft and sustained antibiotic therapy is the usual approach to maximize the chance of renal recovery, but as this case shows graft removal is not always possible. PATIENT CONCERNS: A 35-year-old man with intractable and recurrent fever had acute renal failure in sustained antibiotic therapy. DIAGNOSES: Renal biopsy suggested crescentic glomerulonephritis. fluorodeoxyglucose/positron emission tomography-computed tomography showed increased metabolic activity at the site of aortic graft, reminding that chronic infection of an implanted graft can lead to severe glomerulonephritis. TGFBR2 c.1133G>T mutation was observed in mutation analysis, which was reported to be associated with Loeys-Dietz syndrome. INTERVENTIONS: Although infection was properly controlled with appropriate antimicrobial treatment, his renal dysfunction did not improve. A short-term inclusion of low-dose corticosteroid significantly benefit without introducing harm. OUTCOMES: He partly recovered from renal injury. LESSONS: In patients with glomerulonephritis triggered by a long-duration infection, low-dose corticosteroid therapy may be considered when renal dysfunction secondary to nephritis does not improve after appropriate antimicrobial treatment.

Morphologic performance analysis of the Relay nonbare stent graft in dissected thoracic aorta.

OBJECTIVE: The aim of this study was to evaluate morphologic changes in dissected aortas after thoracic endovascular aortic repair (TEVAR) with the use of the Relay Nonbare stent graft stent graft by focusing on the geometric stent graft's performance in remodeling aortas. METHODS: We conducted a retrospective three-dimensional computed tomography analysis preoperatively, postoperatively, and 6 months after TEVAR in patients with residual dissection after type A and those with acute and chronic type B dissections at two German centers. RESULTS: Thirty-nine acute and 54 chronic aortic dissections were included. Median follow-up was 200 (interquartile range, 109-617) days. TEVAR induced aortic remodeling in both groups. Complete false lumen thrombosis along the stent graft (postoperative, 73%; follow-up, 84%; P < .0001) led to a decrease in aortic diameter at the middle stent graft level (preoperative, 45.9 mm [38.6-56.6] vs follow-up, 43.6 [37.4-52.4] mm; P = .009). True lumen expansion was observed in both groups and peaked in acute dissections in the distal landing zone (acute, +9.3 mm vs chronic, +5.8 mm; P < .0001). Migration was 2 (0-5) mm, and bird-beak and endoleak type IA rates were 20% and 4%, respectively. There was no retrograde type A dissection. Distal stent graft-induced new entry occurred in 15%; the major risk factor for incidence was the stent graft's wedge apposition angle (odds ratio, 1.365 [confidence interval, 1.115-1.671]; P = .003). CONCLUSIONS: TEVAR with the use of the Relay NBS promotes aortic remodeling in acute and chronic dissections, entailing a low risk of migration, type IA endoleaks, and retrograde type A dissections. Wedge apposition was the predominant risk factor for distal stent graft-induced new entry.

Fluorescence Video Angiography for Evaluation of Dynamic Perfusion Status in an Aneurysm Preclinical Experimental Setting.

BACKGROUND: Experimental studies to assess aneurysm occlusion or perfusion typically rely on macroscopic examination or histological analysis but cannot assess dynamic perfusion. OBJECTIVE: To describe an easy-to-implement and inexpensive fluorescence angiographic technique for the in vivo assessment and imaging of the dynamic perfusion status of aneurysms and their underlying blood vessels in a rat model. METHODS: In a rat sidewall aneurysm model, the angiographic setup included 2 bandpass filters, a video camera, and a bicycle spotlight. After 48 rats underwent fluorescein angiography, dissections were performed to confirm the perfusion status by macroscopic and histologic examination of the aneurysm. RESULTS: Direct injection of 0.2 mL fluorescein 10% Faure achieved strong, clear visibility in all 48 aneurysms. Macro-/microscopic examination identified residual perfusion in 25 and complete healing in 23 aneurysms. Fluorescein imaging identified 21 of these 25 aneurysms (84%) with residual perfusion and 22 of 23 aneurysms (96%) with no residual perfusion. CONCLUSION: Our fluorescein imaging technique proved efficient for the evaluation of aneurysm patency and parent artery integrity in this experimental setting. Fluorescein is nontoxic, can be re-administered if needed, and, in this technique, can expand the armamentarium for the preclinical evaluation of dynamic perfusion status.

Lanthanum carbonate, a phosphate binder, inhibits calcification of implanted aortic allografts in a rat model.

OBJECTIVES: Calcification is one of the major postoperative problems after aortic allograft implantation. We hypothesized that phosphate binders, lanthanum carbonate and calcium carbonate inhibit calcification of implanted aortic allografts and verified this hypothesis using a rat model. METHODS: Aortas were harvested from 4-week-old Brown Norway rats and implanted into the subdermal space of 4-week-old Lewis rats. Twenty-seven recipient Lewis rats were divided into Group N, Group L, and Group C (9 rats per group), which were fed a normal diet, a normal diet containing 3% lanthanum carbonate, and a normal diet containing 3% calcium carbonate, respectively. Implanted aortic allografts were explanted 2 weeks later. Calcification of aortic allografts was evaluated using von Kossa staining and calcium content assay. Calcification score was defined in von Kossa staining as 0 (none), 1 (mild), 2 (moderate), and 3 (severe). Serum calcium and phosphorus levels at euthanasia were measured. RESULTS: Calcification scores were 2.6, 1.2, and 0.8, and calcium content was 48.9, 15.8, and 8.9 mg/dry·g, in Groups N, L, and C, respectively. Calcification was significantly reduced in Groups L and C. Serum calcium level was 11.5, 12.2, and 13.5 mg/dl, and serum phosphorus level was 15.4, 12.5, and 11.7 mg/dl, in Groups N, L, and C, respectively. Serum calcium level in Group C was significantly higher than in the other two groups. CONCLUSIONS: Lanthanum carbonate and calcium carbonate significantly reduced calcification of implanted aortic allografts in young rats. Although calcium carbonate induced hypercalcemia, lanthanum carbonate has significant potential to inhibit calcification of implanted aortic allografts.

Bridge to Transplantation With Long-Term Mechanical Assist Devices in Adults With Transposition of the Great Arteries.

Prior to the widespread adoption of the arterial switch operation, patients with transposition of the great arteries (TGA) commonly underwent atrial switch operation (Mustard or Senning). It is not uncommon for these patients to progress to end stage heart failure and increasingly ventricular assist devices (VADs) are used to support these patients as a bridge to transplantation, though there is limited experience with this worldwide. A retrospective review of our institution's VAD database was undertaken and revealed seven adult patients with a history of TGA and subsequent systemic ventricular failure were implanted with a VAD: four of whom received the VAD as a bridge to transplantation (BTT) at the time of implantation, two who were initially designated as destination therapy secondary to severe pulmonary hypertension, and one who was designated as destination therapy secondary to a high risk of life-threatening non-compliance. Seven patient cases who received a VAD for severe systemic ventricular failure were included in this study. The mean age of the patients was 40 years and the majority of patients were male (6/7, 85%). Five of the patients (71.4%) had previously undergone an atrial switch operation and all of these were Mustard procedures. Two of the seven patients (28.5%) had congenitally corrected transposition of the great arteries (CC-TGA). Two of the seven patients (28.5%) had supra-systemic pulmonary pressures before VAD implantation and were designated as destination therapy (DT). One of these patients was later designated as BTT as an improvement in his pulmonary vascular resistance was observed, and subsequently underwent heart transplantation. Because of anatomic considerations, four of the patients (57%) underwent redo-sternotomy with outflow cannula anastomosis to the ascending aorta, one patient underwent VAD implantation via a left subcostal incision with anastomosis of the outflow graft to the descending thoracic aorta, and two patients (28.5%) underwent VAD implantation via a left thoracotomy and anastomosis of the outflow cannula to the descending thoracic aorta. Six of the seven patients had a HeartWare HVAD VAD implanted; one received a Thoratec Heartmate II VAD. Two patients underwent VAD explant and orthotopic heart transplant, 222 days and 444 days after VAD implant, respectively. One patient died on postoperative day 17 after complications from recurrent VAD thrombosis despite multiple pump exchanges. Four patients remain on VAD support, three of these patients are awaiting transplantation at last follow-up (mean days on support, 513 days). Bridge to transplantation with a durable VAD is technically feasible and relatively safe in patients with TGA. Multiple redo-sternotomies can be avoided with a left posterior thoracotomy approach and outflow graft anastomosis to the descending thoracic aorta after careful anatomic considerations.

Aortic Arch Homograft Reconstruction of Nonconfluent Pulmonary Arteries During Extracardiac Fontan.

Reconstruction of nonconfluent pulmonary arteries during Fontan completion is a challenging technical issue. In this case report, we describe the use of an aortic homograft, including the aortic arch, to complete a Fontan and reconstruct the pulmonary artery confluence in a child with discontinuous pulmonary arteries and bilateral superior caval veins who had undergone bilateral unidirectional Glenn palliation. The configuration of the aortic homograft was ideal to ensure laminar flow from the inferior vena cava to both pulmonary arteries and in maintaining durable elastance posterior to the native aorta.

Targeting Phosphodiesterase-5 by Vardenafil Improves Vascular Graft Function.

OBJECTIVES: Ischaemia reperfusion (IR) injury occurs during vascular graft harvesting and implantation during vascular/cardiac surgery. Elevated intracellular cyclic guanosine monophosphate (cGMP) levels contribute to an effective endothelial protection in different pathophysiological conditions. The hypothesis that the phosphodiesterase-5 inhibitor vardenafil would protect vascular grafts against IR injury by upregulating the nitric oxide-cGMP pathway in the vessel wall of the bypass graft was investigated. METHODS: Lewis rats (n = 6-7/group) were divided into Group 1, control; Group 2, donor rats received intravenous saline; Group 3, received intravenous vardenafil (30 µg/kg) 2 h before explantation. Whereas aortic arches of Group 1 were immediately mounted in an organ bath, aortic segments of Groups 2 and 3 were stored for 2 h in saline and transplanted into the abdominal aorta of the recipient. Two hours after transplantation, the implanted grafts were harvested. Endothelium dependent and independent vasorelaxations were investigated. TUNEL, CD-31, ICAM-1, VCAM-1, α-SMA, nitrotyrosine, dihydroethidium and cGMP immunochemistry were also performed. RESULTS: Compared with the control, the saline group showed significantly attenuated endothelium dependent maximal relaxation (Rmax) 2 h after reperfusion, which was significantly improved by vardenafil supplementation (Rmax control, 91 ± 2%; saline 22 ± 2% vs. vardenafil 39 ± 4%, p < .001). Vardenafil pre-treatment significantly reduced DNA fragmentation (control 9 ± 1%, saline 66 ± 8% vs. vardenafil 13 ± 1%, p < .001), nitro-oxidative stress (control 0.8 ± 0.3, saline 7.6 ± 1.3 vs. vardenafil 3.8 ± 1, p = .036), reactive oxygen species level (vardenafil 36 ± 4, control 34 ± 2 vs. saline 43 ± 2, p = .049), prevented vascular smooth muscle cell damage (control 8.5 ± 0.7, saline 4.3 ± 0.6 vs. vardenafil 6.7 ± 0.6, p = .013), decreased ICAM-1 (control 4.1 ± 0.5, saline 7.0 ± 0.9 vs. vardenafil 4.4 ± 0.6, p = .031), and VCAM-1 score (control 4.4 ± 0.4, saline 7.3 ± 1.0 vs. vardenafil 5.2 ± 0.4, p = .046) and increased cGMP score in the aortic wall (control 11.2 ± 0.8, saline 6.5 ± 0.8 vs. vardenafil 8.9 ± 0.6, p = .016). The marker for endothelial integrity (CD-31) was also higher in the vardenafil group (control 74 ± 4%, saline 22 ± 2% vs. vardenafil 40 ± 3%, p = .008). CONCLUSIONS: The results support the view that impairment of intracellular cGMP signalling plays a role in the pathogenesis of the endothelial dysfunction of an arterial graft after bypass surgery, which can effectively be prevented by vardenafil. Its clinical use as preconditioning drug could be a novel approach in vascular/cardiac surgery.