Sequential Surgical Procedures in Vascular Surgery Patients Are Associated With Perioperative Adverse Cardiac Events

Patients at elevated cardiovascular risk are prone to perioperative cardiovascular complications, like myocardial injury after non-cardiac surgery (MINS). We have demonstrated in a mouse model of atherosclerosis that perioperative stress leads to an increase in plaque volume and higher plaque vulnerability. Regulatory T cells (Tregs) play a pivotal role in development and destabilization of atherosclerotic plaques. For this exploratory post-hoc analysis we identified 40 patients recruited into a prospective perioperative biomarker study, who within the inclusion period underwent sequential open vascular surgery. On the basis of protein markers measured in the biomarker study, we evaluated the perioperative inflammatory response in patients' plasma before and after index surgery as well as before and after a second surgical procedure. We also analyzed available immunohistochemistry samples to describe plaque vulnerability in patients who underwent bilateral carotid endarterectomy (CEA) in two subsequent surgical procedures. Finally, we assessed if MINS was associated with sequential surgery. The inflammatory response of both surgeries was characterized by postoperative increases of interleukin-6,−10, Pentraxin 3 and C-reactive protein with no clear-cut difference between the two time points of surgery. Plaques from CEA extracted during the second surgery contained less Tregs, as measured by Foxp3 staining, than plaques from the first intervention. The 2nd surgical procedure was associated with MINS. In conclusion, we provide descriptive evidence that sequential surgical procedures involve repeat inflammation, and we hypothesize that elevated rates of cardiovascular complications after the second procedure could be related to reduced levels of intraplaque Tregs, a finding that deserves confirmatory testing and mechanistic exploration in future populations.

Targeting Chemokine Receptor CXCR4 and Translocator Protein for Characterization of High-Risk Plaque in Carotid Stenosis Ex Vivo

Background and Purpose- This pilot study aims to demonstrate the feasibility of targeting molecular characteristics of high-risk atherosclerotic plaque in symptomatic and asymptomatic carotid stenosis (CS), that is, upregulation of the translocator protein (TSPO) and the chemokine receptor type 4 (CXCR4), by means of molecular imaging. Methods- In a translational setting, specimens of carotid plaques of patients with symptomatic and asymptomatic CS obtained by carotid endarterectomy were analyzed for the presence of TSPO and CXCR4 by autoradiography, using the positron emission tomography tracers ¹⁸F-GE180 and ⁶⁸Ga-Pentixafor and evaluated by histopathology. In addition, ⁶⁸Ga-Pentixafor positron emission tomography/computed tomography was performed in a patient with high-grade CS. Results- Distinct patterns of upregulation of TSPO (¹⁸F-GE180 uptake) and CXCR4 (⁶⁸Ga-Pentixafor uptake) were identified in carotid plaque by autoradiography. The spatial distribution was associated with specific histological hallmarks that are established features of high-risk plaque: TSPO upregulation correlated with activated macrophages infiltration, whereas CXCR4 upregulation also corresponded to areas of intraplaque hemorrhage. ⁶⁸Ga-Pentixafor uptake was significantly higher in plaques of symptomatic compared with asymptomatic CS. Clinical positron emission tomography revealed marked ⁶⁸Ga-Pentixafor uptake in carotid plaque of a patient with high-grade CS. Conclusions- Clinical imaging of molecular signatures of high-risk atherosclerotic plaque is feasible and may become a promising diagnostic tool for comprehensive characterization of carotid disease. This methodology provides a platform for future studies targeting carotid plaque.

Adrenomedullin Is Associated With Surgical Trauma and Impaired Renal Function in Vascular Surgery Patients

BACKGROUND:

Patients undergoing vascular surgery are prone to perioperative organ injury because of both higher prevalence of cardiovascular risk factors and the extent of surgery. Early detection of organ failure is essential to facilitate appropriate medical care. Midregional pro-adrenomedullin (MR-proADM) has been investigated in acute medical care settings to guide clinical decision-making regarding patient pathways and to identify patients prone to imminent cardiovascular or inflammatory complications. In this study, we evaluated the impact of perioperative MR-proADM levels as an early marker of perioperative cardiovascular and inflammatory stress reactions and kidney injury.

METHODS:

The study was conducted as a monocentric, prospective, noninterventional trial at Hannover Medical School, Germany. A total of 454 consecutive patients who underwent open vascular surgery were followed from the day prior to until 30 days after surgery. The composite primary end point was defined as the occurrence of major adverse cardiac events (MACEs), acute kidney injury (AKI), or systemic inflammatory response syndrome (SIRS). Measurements were correlated with both medical history and postoperative MACE, AKI, or SIRS using univariate and multivariate regression analysis.

RESULTS:

One hundred thirty-nine (31%) of the patients reached the primary end point within the study interval. Midregional pro-adrenomedullin change was associated with the combined primary end point and with the intensity of surgical trauma. Midregional pro-adrenomedullin change was increased in patients reaching the secondary end points, SIRS (optimal cutoff: 0.2 nmol/L) and AKI (optimal cutoff: 0.7 nmol/L), but not in patients with MACEs.

CONCLUSION:

Increased levels of MR-proADM within the perioperative setting (1) were linked to the invasiveness of surgery and (2) identified patients with ongoing loss of renal function. Increased MR-proADM levels may therefore identify a subgroup of patients prone to excessive cardiovascular stress but did not directly correlate with adverse cardiac events. Consistently low levels of MR-proADM may identify a subgroup of patients with acceptable low risk to guide discharge from high-density care units.

Streptococcus mitis and Gemella haemolysans were simultaneously found in atherosclerotic and oral plaques of elderly without periodontitis-a pilot study

OBJECTIVES

Local infections may contribute to the initiation and progression of several clinical diseases in humans. Atherosclerotic plaques of subjects suffering from periodontitis are colonized by periopathogens; however, the presence of bacteria in atherosclerotic plaques in patients without severe forms of periodontitis is of high relevance for the general population.

MATERIALS AND METHODS

Patients who were electively treated for atherosclerotic lesions of the carotid artery and without clinical signs of periodontitis were eligible for the study. Oral and atherosclerotic plaques were sampled, processed, and analyzed for their microbial composition by 454-sequencing.

RESULTS

Seventeen patients were included in the analyses, and 76 % of all atherosclerotic plaque specimens were positive for bacterial DNA. In the oral plaques, 76,532 sequences were identified representing 1 phylum, 17 classes, 112 families, and 263 genera. In atherosclerotic plaques, 6112 sequences representing 1 phylum, 4 classes, 8 families, and 36 genera were found. The bacterial DNAs of the species Gemella haemolysans and Streptococcus mitis were simultaneously found in atherosclerotic as well as oral plaque samples of 3 patients.

CONCLUSIONS

These results indicated that in subjects without periodontitis, the transmission of oral bacteria to atherosclerotic plaques of the carotid artery is a feasible event.

CLINICAL RELEVANCE

The prevention of transient bacteremia from the oral cavity requires high levels of oral health.

Monocyte Subsets and Related Chemokines in Carotid Artery Stenosis and Ischemic Stroke

Carotid stenosis (CS) is an important cause of ischemic stroke. However, reliable markers for the purpose of identification of high-risk, so-called vulnerable carotid plaques, are still lacking. Monocyte subsets are crucial players in atherosclerosis and might also contribute to plaque rupture. In this study we, therefore, aimed to investigate the potential role of monocyte subsets and associated chemokines as clinical biomarkers for vulnerability of CS. Patients with symptomatic and asymptomatic CS (n = 21), patients with cardioembolic ischemic strokes (n = 11), and controls without any cardiovascular disorder (n = 11) were examined. Cardiovascular risk was quantified using the Essen Stroke Risk Score (ESRS). Monocyte subsets in peripheral blood were measured by quantitative flow cytometry. Plaque specimens were histologically analyzed. Furthermore, plasma levels of monocyte chemotactic protein 1 (MCP-1) and fractalkine were measured. Intermediate monocytes (Mon2) were significantly elevated in symptomatic and asymptomatic CS-patients compared to controls. Mon2 counts positively correlated with the ESRS. Moreover, stroke patients showed an elevation of Mon2 compared to controls, independent of the ESRS. MCP-1 levels were significantly higher in patients with symptomatic than in those with asymptomatic CS. Several histological criteria significantly differed between symptomatic and asymptomatic plaques. However, there was no association of monocyte subsets or chemokines with histological features of plaque vulnerability. Due to the multifactorial influence on monocyte subsets, the usability as clinical markers for plaque vulnerability seems to be limited. However, monocyte subsets may be critically involved in the pathology of CS.

Resistance to infection of long-term cryopreserved human aortic valve allografts

OBJECTIVE

To analyze the in vitro antimicrobial activity of 3 antibiotic regimens (group A, gentamicin-piperacillin-vancomycin-metronidazole-amphotericin B; group B, gentamicin-piperacillin-flucloxacillin-metronidazole-amphotericin B; and group C, meropenem-vancomycin-tobramycin-colistin-amphotericin B) used in the processing of cryopreserved human ascending aortic tissue and aortic valves against Staphylococcus epidermidis and Staphylococcus aureus. The results were additionally compared with the infection resistance of cryopreserved ascending aortic tissue against Escherichia coli and Pseudomonas aeruginosa.

MATERIALS

Each of 10 cryopreserved human allografts (CHAs) was divided into 25 pieces (separating aortic wall and valve). Eighteen segments were microbiologically tested, and 7 pieces underwent scanning electron microscopy. A bacterial solution (4 mL; optical density, 0.20 ± 0.02) was used for contamination. After incubation, the optical density of the solution was measured. CHAs underwent sonication to release viable adherent bacteria. The number of attached bacteria was quantified by the colony forming units per square centimeter of CHA surface.

RESULTS

Antibiotic regimen groups B and C were more efficient than group A in eradicating gram-positive organisms adherent to the aortic wall (P < .001). Group C showed enhanced resistance against E coli compared with group A or B (P < .001), whereas group B appeared to be more effective against P aeruginosa (P < .001). With reference to each antibiotic regimen, ascending aortic tissue showed significantly less bacterial contamination with staphylococcal bacteria than valve grafts (P ≤ .01).

CONCLUSIONS

CHAs possess antibacterial activity despite long-term storage over 5 years. Antibiotic combinations applied during CHA processing have a significant influence on their infection resistance. Ascending aortic tissue shows a significantly enhanced bacterial resistance against staphylococcal bacteria compared with aortic valves.

Intraoperative Changes in Cerebrospinal Fluid Gas Tensions Reflect Paraplegia During Thoracoabdominal Aortic Surgery

Background:

In this study, gas tensions in cerebrospinal fluid (CSF) were prospectively evaluated as intraoperative markers for the detection of neurological deficits.

Methods:

Spinal fluid, serum, and heart lung machine (HLM) perfusate were monitored for gas tensions (po2/pCo2) and related parameters (pH, lactate, and glucose) during thoracoabdominal aortic repair and correlated with perioperative neurological examination and electrophysiological testing.

Results:

Forty-seven patients were assessed for the study, and 40 consecutive patients were finally included. The patients were divided into 3 groups: group A (23 patients, 57.5%): no clinical or laboratory signs of neurological damage; group B (14 patients, 35%) who developed subclinical deficits; and group C (3 patients, 7.5%) who had paraplegia. Significant intraoperative changes in CSF gas tensions were observed with postoperative paraplegia. Glucose ratio between serum and CSF showed higher variability in group C, confirming a damage of the blood–brain barrier (BBB).

Conclusion:

Major neurological damage is reflected by early changes in CSF gas tensions and glucose variability, suggesting damage of the BBB in these patients.

Renal function interferes with copeptin in prediction of major adverse cardiac events in patients undergoing vascular surgery

OBJECTIVE

Precise perioperative risk stratification is important in vascular surgery patients who are at high risk for major adverse cardiovascular events (MACE) peri- and postoperatively. In clinical practice, the patient's perioperative risk is predicted by various indicators, e.g. revised cardiac index (RCRI) or modifications thereof. Patients suffering from chronic kidney disease (CKD) are stratified into a higher risk category. We hypothesized that Copeptin as a novel biomarker for hemodynamic stress could help to improve the prediction of perioperative cardiovascular events in patients undergoing vascular surgery including patients with chronic kidney disease.

METHODS

477 consecutive patients undergoing abdominal aortic, peripheral arterial or carotid surgery from June 2007 to October 2012 were prospectively enrolled. Primary endpoint was 30-day postoperative major adverse cardiovascular events (MACE).

RESULTS

41 patients reached the primary endpoint, including 63.4% aortic, 26.8% carotid, and 9.8% peripheral surgeries. Linear regression analysis showed that RCRI (P< .001), pre- (P< .001), postoperative Copeptin (P< .001) and Copeptin level change (P= .001) were associated with perioperative MACE, but CKD remained independently associated with MACE and Copeptin levels. Multivariate regression showed that increased Copeptin levels added risk predictive information to the RCRI (P= .003). Especially in the intermediate RCRI categories was Copeptin significantly associated with the occurrence of MACE. (P< .05 Kruskal Wallis test). Subdivision of the study cohort into CKD stages revealed that preoperative Copeptin was significantly associated with CKD stages (P< .0001) and preoperative Copeptin measurements could not predict MACE in patients with more severe CKD stages.

CONCLUSION

Preoperative Copeptin loses its risk predictive potential for perioperative MACE in patients with chronic kidney disease undergoing vascular surgery.

The role of pericyte detachment in vascular rarefaction

BACKGROUND

Pericytes surround endothelial cells at the perivascular interface. Signaling between endothelial cells and pericytes is crucial for capillary homeostasis, as pericytes stabilize vessels and regulate many microvascular functions. Recently it has been shown that pericytes are able to detach from the vascular wall and contribute to fibrosis by becoming scar-forming myofibroblasts in many organs including the kidney. At the same time, the loss of pericytes within the perivascular compartment results in vulnerable capillaries which are prone to instability, pathological angiogenesis, and, ultimately, rarefaction.

AIMS

This review will give an overview of pericyte-endothelial cell interactions, summarize the signaling pathways that have been identified to be involved in pericyte detachment from the vascular wall, and present pathological endothelial responses in the context of disease of the kidney.

Neoadjuvant targeted therapy in a primary metastasized renal cell cancer patient leads to down-staging of inferior vena cava thrombus (IVC) enabling a cardiopulmonary bypass-free tumor nephrectomy: a case report

BACKGROUND

We report on a 62-year-old gentleman presenting at our urological department with an advanced renal cell cancer of the right kidney (10 cm in diameter), with an extensive caval vein thrombus (level IV) and bilateral pulmonary metastases. Another suspicious lesion at the left hemithorax was radiologically described.

METHOD

A presurgical, neoadjuvant systemic therapy with sunitinib, a tyrosine kinase inhibitor, was initiated for 4 cycles in total (50 mg/day; 4 weeks on/2 weeks off). The cytoreductive nephrectomy was performed following the fourth cycle of sunitinib and after a 14-day break. Transesophageal echocardiography was used for intraoperative monitoring of the caval vein thrombus. Systemic treatment with sunitinib was continued 4 weeks after surgery.

RESULTS

A significant reduction in tumor size, metastatic sites and down-staging of IVC from level IV to level III according to Novick classification was achieved.

CONCLUSION

Significant down-staging of the tumor caval vein thrombus which initially reached the right atrium enabled us to perform surgery limited to the abdominal cavity without extracorporeal circulation nor hypothermia.

Effects of the ABO-mismatch between donor and recipient of cryopreserved arterial homografts

AIM

Cryopreserved arterial homograft (CAH) is a well-established substitute material for in situ reconstruction of vascular infections. However, their degeneration remains serious complication. Although several studies propose ABO-mismatching between CAH-donor and -recipient as the main reason, the results are controversial. We compared the outcome between ABO-compatible and ABO-incompatible CAH recipients to evaluate the contribution of ABO-mismatching.

METHODS

Between January 2004 and December 2007, a retrospective review in 32 patients who underwent CAH-implantation was performed. The patients were divided in ABO-incompatible (group A: 17/32 patients; 53%) and ABO-compatible (group B: 15/32 patients; 47%) to CAH donor. Leucocytes, platelets and C-reactive protein (CRP) levels were recorded during the in-hospital stay. These were correlated with the surface of implanted homograft (SIH). Mid-term survival- and freedom-from-reoperation (FFR) rates were also calculated.

RESULTS

In both groups, peak of leucocytes and CRP was recorded on third postoperative day (POD3) and regarding platelets lowest values on POD1. Interestingly, a second CRP-peak was reported on POD8 in group A (A: 172±104mg/L vs. B: 75±55mg/L, P=0.01). No relationship between second CRP-peak and SIH was found. After 27 months median follow-up (range, 5-49 months), survival- (65% vs. 84%, P=0.28) and FFR-rates (94% vs. 93%, P=0.98) remained comparable.

CONCLUSION

We consider that the second CRP-peak expresses an early cytoimmunologic response of ABO-incompatible recipients against CAH. However, we did not find any relationship between ABO-incompatibility and poor mid-term outcome in terms of reoperation or mortality. Longer surveillance of our patients is mandatory.

Vascular complications in patients undergoing femoral cannulation for extracorporeal membrane oxygenation support

BACKGROUND

Extracorporeal membrane oxygenation (ECMO) is a well-established treatment for severe cardiopulmonary failure. Patients undergoing ECMO support through femoral vessels are prone to vascular complications. The aim of this study was to evaluate such complications to outline basic technical principles for their prevention.

METHODS

From January 2005 to December 2009, 174 patients underwent ECMO support through cannulation of the femoral vessels. The primary outcome was any vascular complication. Secondary outcomes were 30-day mortality and 1-year survival. A logistic regression analysis including ECMO duration, peripheral arterial disease, ECMO access (percutaneous versus open), and diabetes mellitus identified predictors for vascular complications.

RESULTS

The venoarterial mode was used in 143 patients (82%), and venovenous in 31 patients (18%). Of the 17 (10%) observed vascular complications, 15 (88%) occurred in patients with venoarterial access, whereas 2 (12%) occurred after venovenous access (p=0.50) Two patients who had extremity ischemia required limb amputation. Thirty-day mortality and 1-year survival rates were 63% and 26%, respectively. Peripheral arterial disease was the only strong predictor of vascular complications (odds ratio, 6.95; 95% confidence interval, 1.89 to 25.59; p=0.003). Vascular complications were not associated with early or late mortality.

CONCLUSIONS

The incidence of vascular complications in venovenous cannulation was low, whereas in arterial cannulation, it is still considerable. Peripheral arterial disease remains a risk factor, and early involvement of vascular surgeons for open vascular exposure or alternative vascular access sites can be recommended. Vascular complications after ECMO support are not associated with higher mortality rates.

Cryopreserved arterial homografts vs silver-coated Dacron grafts for abdominal aortic infections with intraoperative evidence of microorganisms

OBJECTIVE

The gold standard for the treatment of abdominal aortic infections remains controversial. Cryopreserved arterial homografts and silver-coated Dacron grafts have both been advocated as reasonable grafts. Direct clinical or experimental comparisons between these two treatment options have not been published before. This study compared cryopreserved arterial homografts and silver-coated Dacron grafts for the treatment of abdominal aortic infections in a contaminated intraoperative field.

METHODS

From January 2004 to December 2009, 56 patients underwent in situ arterial reconstruction for an abdominal aortic infection. Patients with negative intraoperative microbiologic specimens were excluded. We compared 22 of 36 patients (61%) receiving cryopreserved arterial homografts (group A) vs 11 of 20 (55%) receiving a silver-coated Dacron graft (group B). Primary outcomes were survival and limb salvage; secondary outcomes were graft patency and reinfection. Direct costs of therapy were also calculated.

RESULTS

Thirty-day mortality was 14% in group A and 18% in group B (P >.99), and 2-year survival rates were 82% and 73%, respectively (P = .79). After 2 years, limb salvage was 96% and 100%, respectively (P = .50), whereas graft patency was 100% for both groups. Major complications were an aneurysmal degeneration in group A and graft reinfection in group B (n = 2). Median direct costs of therapy (in US $) were $41,697 (range, $28,347-$53,362) in group A and $15,531 (range, $11,310-$22,209) in group B (P = .02).

CONCLUSIONS

Our results show comparable effectiveness between cryopreserved arterial homograft and silver-coated Dacron graft in the contaminated operative field with respect to early mortality and midterm survival. Graft-inherent complications, aneurysmal degeneration for homografts, and reinfection for silver graft, were also observed. The in situ arterial reconstruction with homografts is nearly three times more expensive than with silver graft.

Surgical outcome in patients with concomitant-infected abdominal aortic aneurysm and spondylitis

The coexistence of infected abdominal aortic aneurysms and spondylitis is rare but challenging. The etiology of the infection is frequently unknown. The aim of this study was to review the outcome of surgical repair of this complex disease. From 2004 to 2006, six patients were identified who underwent surgical repair of concomitant infected abdominal aortic aneurysm and spondylitis. Diagnosis, treatment and intermediate-term results are presented. The clinical manifestation included the signs of ongoing systemic infection, neurological deficit and abdominal or back pain. Computed tomography revealed abdominal aortic aneurysms associated with polysegmental spondylitis. Patients underwent radical debridement and aortic replacement with cryopreserved aortic allografts or silver-coated prostheses followed by antibiotic treatment. Only one patient received a simultaneous anterior vertebral stabilization. Greater omentum was placed in the abscess cavity. Intensive care unit and hospital stay averaged 3.0 and 28.0 days, respectively. Organisms were identified in all but one patient. Over a follow-up period of 4.4 years, four patients are alive and showing freedom from infection, and two patients had died unrelated at seven and eight months. In conclusion, surgical repair of infected aortic aneurysms with resection of infected tissues and implantation of a homograft or a silver-coated prosthesis achieved favorable results in this sick patient group. Simultaneous vertebral stabilization is rarely necessary.

Early neurologic outcome after bovine pericardium versus venous patch angioplasty in 599 patients undergoing carotid endarterectomy

Bovine pericardium was compared to great saphenous vein patch angioplasty regarding the neurologic events after carotid endarterectomy (CEA) with or without concomitant cardiac surgery (CS). From January 1996 to December 2007, 599 patients undergoing CEA (259 with concomitant CS) were enrolled; 456 patients were treated with the great saphenous vein (GSV group) and 143 were treated with bovine pericardium (BP group). Neurologic outcome and Rankin score (RS) were recorded after 24 hours and 30 days. We found comparable rates of neurologic complications (transient ischemic attack, stroke) between the two groups. Thirty-day mortality was 4% (17 of 456 patients) in the GSV group and 0% in the BP group (p = .12). None of the patients died as a consequence of a fatal stroke. Preoperative RS was a prognostic factor for postoperative neurologic deterioration (p = .001). Early neurologic outcome was comparable for the two types of patch material. Preoperative RS predicted postoperative neurologic deterioration.

Eight-year experience with cryopreserved arterial homografts for the in situ reconstruction of abdominal aortic infections

OBJECTIVE

This study investigated short-term and long-term outcomes in patients with abdominal aortic infection (mycotic aneurysm, prosthetic graft infection, aortoenteric fistula) managed by total excision of the aneurysm or the infected vascular graft and in situ aortic reconstruction with a cryopreserved arterial homograft (CAH).

METHODS

From January 2000 to December 2008, 110 consecutive patients underwent CAH implantation for treatment of vascular infections. In 57 (52%), in situ revascularization of the abdominal aorta with Y-prosthesis constructed from CAHs was performed. Early outcome included 30-day mortality and the levels of daily blood markers (leucocytes, C-reactive protein, and platelets) during the postsurgical 10-day period. We reported long-term survival and freedom from reoperation rates, including all indications for reoperation.

RESULTS

Indications for operation were infected vascular graft in 31 patients (55%), aortodigestive fistulae in 11 (19%), nonruptured mycotic aneurysms in 4 (7%), and ruptured mycotic aneurysms of abdominal aorta in 11 (19%). In 39 of 57 patients (68%), the intraoperative specimens were positive for at least one microorganism, and Staphylococcus aureus was present in 14 (25%). In 32 patients (82%) with intraoperative specimens positive for microorganisms, there was no evidence of the intraoperatively detected microorganisms in the postoperative specimens (wound, blood culture, and drainage fluid). The peak value of leucocytes (13.7 +/- 4.4 x 10(3)/L) and C-reactive protein (200 +/- 75 mg/L) occurred on postoperative day 3. Platelets reached the lowest value on postoperative day 2 (178 +/- 67 x 10(9)/L). Median peak body temperature was 37.7 degrees +/- 0.6 degrees C. Thirty-day mortality was 9% (5 of 57 patients). Median follow-up was 36 months (range, 4-118 months); 3-year survival was 81%, and freedom from reoperation was 89%. Five patients (9%) required reoperation, in one patient each for postoperative bleeding, acute cholecystitis, homograft occlusion, homograft-duodenum fistula, and aneurysmal degeneration. No recurrence of infection was reported.

CONCLUSION

These results demonstrate an encouraging outcome after cryopreserved allograft implantation for the treatment of vascular infections in the abdominal aorta. The data represent a basis for future comparisons with other treatment modalities for vascular infections, including silver-coated prostheses and autogenous femoral veins.

Contralateral internal carotid artery occlusion impairs early but not 30-day stroke rate following carotid endarterectomy

Neurological complications and mortality within 30 days following carotid endarterectomy (CEA) alone or with concomitant cardiac surgery/cardiopulmonary bypass (CPB) were assessed in patients with or without contralateral occlusion of the internal carotid artery (CO-ICA).Of 335 patients undergoing CEA, 173 underwent concomitant cardiac surgery with CPB. Group A consisted of 260 patients without CO-ICA and group B of 75 patients with CO-ICA. The neurological complications (peripheral nerve damage, transient ischemic attack [TIA], prolonged reversible ischemic neurological deficit [PRIND], and stroke) and the Rankin index within 24 hours and 30 days postoperatively were compared. Strokes within 24 hours were significantly increased (P = .006) in group B (11%) compared with A (3.1%); TIA and PRIND did not differ (P = .33). The overall neurological complications and in particular for peripheral neurological damage, TIA/PRIND, and stroke did not differ within the 30-day-period postsurgery. A significantly higher stroke rate within 24 hours postsurgery occurred in patients with CO-ICA.

Carotid endarterectomy with or without concomitant aortocoronary bypass in elderly patients: an analysis of 599 procedures

AIM

Carotid endarterectomy (CEA) has been established as an effective treatment of carotid artery disease. Controversial remains the performance of CEA in elderly patients. Aim of this study is to report the mid-term (30 days) neurological outcome in patients older than 75 years after CEA with or without simultaneous aortocoronary bypass (CABG).

METHODS

599 patients undergoing CEA from January 2000 to December 2007 were enrolled. Isolated CEA was performed in 398/599 (66%) patients (group A). In 201/599(34%) patients (group B) was performed a combined procedure (CEA/CABG). 90/398(23%) patients of group A (group A1) and 49/201(24%) patients of group B (group B1) were >75 years old. 308/398 (77%) patients of group A (group A2) and 152/201 (76%) patients of group B (group B2) were <75 years old. Mortality, TIA and stroke rates as well as pre- and postoperative Rankin scale (RS) were reported.

RESULTS

In isolated CEAs, mortality was higher in group A1 (A1:1.1% vs A2:0%, P=0.51). We found no significant differences in rates of TIA (A1:4.4% versus A2:3.2%, P=0.79) or stroke (A1:2.2% versus A2:1.9%, P=0.98). In CEA/CABG, mortality was 0% in group B1 and 5.9% in group B2 (P=0.17). No significant differences in rates of TIA (B1:2% versus B2:3%, P=0.76) or stroke (B1:2% versus B2:5%, P=0.70) were reported. Preoperative RS was the only positive predictor for postoperative stroke in groups A1 (P=0.02) and B1 (P=0.001).

CONCLUSION

CEA is an appropriate and safe procedure in elderly patients. Under consideration should be the performance of CEA in elderly patients with high preoperative RS.

Human iliac vein replacement with a tissue-engineered graft

The modification of a previously described technique to generate venous conduits in a lamb model from a decellularised matrix and autologous cells and its application to human tissue is described. A 49-year-old woman underwent surgery for a large malignant pelvic tumour (carcinoma of unknown primary) involving the right iliac artery and vein. The right iliac artery was reconstructed with a cryopreserved human arterial allograft. For iliac vein reconstruction a tissue-engineered neo-vein was developed utilising a decellularised cryopreserved vein allograft that was reseeded in a bioreactor with autologous endothelial cells derived from the recipient's great saphenous vein. Both interposition grafts were patent initially, after 3, 6, 12, and 24 months, but the tissue-engineered neo-vein had become obstructed due to evolving disease four month postoperatively. Tissue engineered neo-veins may be a therapeutic option in selected cases with symptomatic vein stenosis or obstruction not curable with interventional methods or standard prosthetic replacement.

Homograft patch repair in carotid artery rupture

The case of a 24-year-old man with a rupture of the left common carotid artery and history of intravenous drug abuse is presented. Due to absence of a suitable autologous vein segment the carotid bulb was repaired with a human allograftpatch.

Tissue-Engineering ist mehr als nur Gewebezüchtung

Tissue engineering is a young, multidisciplinary scientific field which aims at generating bioartificial tissues in vitro to restore diseased human organs. This fledgling sector of biosciences emerged few years ago but draws scientific and public attention increasingly, as the recent accomplishments are impressive and promise alternative therapeutic concepts to replace or enhance failing human organs. Tissue engineering using either polymers or decellularized native allogeneic or xenogeneic matrices may provide the techniques to develop the ideal graft. The matrix scaffold can be seeded with cells that organise and develop into tissue prior to or following implantation. This review surveys upon recent developments in the field of in vitro tissue engineering (skin, heart, heart valves, blood vessels, liver, kidney, urogenital, and nerves), without claiming completeness, thus providing an insight into what has been attempted and what may be possible in the near future.

The frozen elephant trunk technique

The so-called 'frozen elephant trunk' technique is adapted from the classical elephant trunk technique first described by H.G. Borst in 1983 and allows the repair of concomitant aortic arch and proximal descending aortic aneurysms in a single stage. A 'hybrid' vascular graft consisting of a conventional tube graft with an endovascular stented graft at the distal end is utilised to achieve a blood-tight seal in the descending aorta that cannot easily be accessed directly from an anterior approach. Thus, the concept of a traditional elephant trunk, otherwise completed with a secondary endovascular or surgical procedure, is achieved in one single step. First intra- and postoperative results of this technique in terms of successful exclusion of the proximal descending aortic aneurysm are good and following the learning curve, the prolongation of circulatory arrest and cerebral perfusion, as compared to the traditional elephant trunk procedure, is within minutes and thus acceptable. Currently all patients with thoracic aneurysms extending from the arch beyond the left subclavian artery are evaluated for this treatment at our institution. Furthermore, acute aortic dissections (type A and B) are an area of intensive clinical evaluation at present.

Severe obstructive calcifications affecting the descending and suprarenal abdominal aorta without coexisting peripheral atherosclerotic disease – coral reef aorta

The case of a 58-year-old woman with leg claudication due to a very rare form of atherosclerosis affecting the descending thoracic and abdominal aorta – known as coral reef aorta – without involvement of the femoro-distal vessels is reported. The patient was treated with a polyester bifurcation graft from the proximal descending aorta to both common iliac arteries via a left dorsal minithoracotomy and a second left retroperitoneal approach. This unusual approach was chosen instead of direct aortic replacement in order to prevent paraplegia. In case of future visceral or left renal malperfusion the diseased artery can be connected to the prosthesis directly or by the use of an additional bypass graft. This would not be the case with a conventional axillo-bifemoral graft.

Tissue Engineering für Herzklappen und Gefäße

Current prosthetic substitutes for heart valves and blood vessels have numerous limitations such as limited durability (biological valves), susceptibility to infection, the necessity of lifelong anticoagulation therapy (prosthetic valves), and reduced patency in small-caliber grafts, for example. Tissue engineering using either polymers or decellularized native allogeneic or xenogenic heart valve/vascular matrices may provide the techniques to develop the ideal heart valve or vascular graft. The matrix scaffold serves as a basis on which seeded cells can organise and develop into the valve or vascular tissue prior to or following implantation. The scaffold is either degraded or metabolised during the formation and organisation of the newly generated matrix, leading to vital living tissue. This paper summarises current research and first clinical developments in the tissue engineering of heart valves and vascular grafts.

Use of a fibrin preparation in the engineering of a vascular graft model

OBJECTIVE

Morphological and functional characterization of cocultured endothelial cells (EC) and myofibroblasts (MFB) seeded on a matrix composed of a fibrin preparation mimicking the microenvironment of a vascular wall.

METHODS

MFB and EC were isolated from human saphenous veins and expanded separately in vitro. MFB were seeded on a composite matrix consisting of a fibrin preparation (with or without transforming growth factor-beta2) and a polyglactin-mesh to form a 3-dimensional structure, which was consecutively reseeded with EC. Seeded matrices were incubated in a bioreactor. Characterization was done including fluorescence staining, live-/dead-assay and immunohistochemistry.

RESULTS

High density cocultures in hierarchical structure mimicking the formation of a vascular wall were obtained with nearly complete coverage of the surface with EC. Distribution of preseeded MFB in a 519+/-27 microm thick layer (day 14) was achieved. Cell viability was shown in fluorescence staining for at least 19 days. In deeper layers, no viable cells could be detected within the fibrin preparation. EC covered the surface, had uniform morphology, and their preserved viability was shown for at least 5 days. No EC-ingrowth was found into the fibrin preparation. Neoformation of the matrix proteins laminin and collagen IV was observed.

CONCLUSION

A structured coculture of MFB and EC was obtained mimicking the formation of a vascular wall with preserved viability utilizing a fibrin preparation. Nutrition problems seem to limit the maximal extent of MFB in the matrix.