Peri-operative Mortality and Morbidity of Complex Abdominal Aortic Aneurysms Repair in Switzerland: A Swissvasc Report.

OBJECTIVE: Complex abdominal aortic aneurysms (cAAA) pose a clinical challenge. The aim of this study was to assess the 30 day mortality and morbidity for open aneurysm repair (OAR) and fenestrated/branched endovascular aortic repair (F/BEVAR), and the effect of hospital volume in patients with asymptomatic cAAA in Switzerland. METHODS: Retrospective, cohort study using data from Switzerland's national registry for vascular surgery, Swissvasc, including patients treated from 1 January 2019 to 31 December 2022. All patients with asymptomatic, true, non-infected cAAA were identified. Primary outcome was 30 day mortality and morbidity reported using the Clavien-Dindo classification. Outcomes were compared between OAR and F/BEVAR after propensity score weighting. RESULTS: Of the 461 patients identified, 333 underwent OAR and 128 underwent F/BEVAR for cAAA. At 30 days, overall mortality rate was 3.3% after OAR and 3.1% after F/BEVAR (p = .76). Propensity scores weighted analysis indicated similar morbidity rates for both approaches: F/BEVAR (OR 0.69, 95% CI 0.45 - 1.05, p = .055); intestinal ischaemia (1.8% after OAR, 3.1% after F/BEVAR, p = .47) and renal failure requiring dialysis (1.5% after OAR, 5.5% after F/BEVAR, p = .024) were associated with highest morbidity and mortality. Treatment specific complications with high morbidity were abdominal compartment syndrome and lower limb compartment syndrome following F/BEVAR. Overall treatment volume was low for most of the hospitals treating cAAA in Switzerland; outliers with increased mortality were identified among low volume hospitals. CONCLUSION: Comparable 30 day mortality and morbidity rates were found between OAR and F/BEVAR for cAAA in Switzerland; lack of centralisation was also highlighted. Organ specific complications driving mortality were renal failure, intestinal ischaemia, and limb ischaemia, specifically after F/BEVAR. Treatment in specialised high volume centres, alongside efforts to reduce peri procedural kidney injury and mesenteric ischaemia, offers potential to lower morbidity and mortality in elective cAAA treatment.

Association of preoperative beta-blocker use and cardiac complications after major noncardiac surgery: a prospective cohort study.

INTRODUCTION: Cardiac complications after major noncardiac surgery are common and associated with high morbidity and mortality. How preoperative use of beta-blockers may impact perioperative cardiac complications remains unclear. METHODS: In a multicentre prospective cohort study, preoperative beta-blocker use was ascertained in consecutive patients at elevated cardiovascular risk undergoing major noncardiac surgery. Cardiac complications were prospectively monitored and centrally adjudicated by two independent experts. The primary endpoint was perioperative myocardial infarction or injury attributable to a cardiac cause (cardiac PMI) within the first three postoperative days. The secondary endpoints were major adverse cardiac events (MACE), defined as a composite of myocardial infarction, acute heart failure, life-threatening arrhythmia, and cardiovascular death and all-cause death after 365 days. We used inverse probability of treatment weighting to account for differences between patients receiving beta-blockers and those who did not. RESULTS: A total of 3839/10 272 (37.4%) patients (mean age 74 yr; 44.8% female) received beta-blockers before surgery. Patients on beta-blockers were older, and more likely to be male with established cardiorespiratory and chronic kidney disease. Cardiac PMI occurred in 1077 patients, with a weighted odds ratio of 1.03 (95% confidence interval [CI] 0.94-1.12, P=0.55) for patients on beta-blockers. Within 365 days of surgery, 971/10 272 (9.5%) MACE had occurred, with a weighted hazard ratio of 0.99 (95% CI 0.83-1.18, P=0.90) for patients on beta-blockers. CONCLUSION: Preoperative use of beta-blockers was not associated with decreased cardiac complications including cardiac perioperative myocardial infarction or injury and major adverse cardiac event. Additionally, preoperative use of beta-blockers was not associated with increased all-cause death within 30 and 365 days. CLINICAL TRIAL REGISTRATION: NCT02573532.

Long-term outcomes of perioperative myocardial infarction/injury after non-cardiac surgery.

AIMS: Perioperative myocardial infarction/injury (PMI) following non-cardiac surgery is a frequent cardiac complication. Better understanding of the underlying aetiologies and outcomes is urgently needed. METHODS AND RESULTS: Aetiologies of PMIs detected within an active surveillance and response programme were centrally adjudicated by two independent physicians based on all information obtained during clinically indicated PMI work-up including cardiac imaging among consecutive high-risk patients undergoing major non-cardiac surgery in a prospective multicentre study. PMI aetiologies were hierarchically classified into 'extra-cardiac' if caused by a primarily extra-cardiac disease such as severe sepsis or pulmonary embolism; and 'cardiac', further subtyped into type 1 myocardial infarction (T1MI), tachyarrhythmia, acute heart failure (AHF), or likely type 2 myocardial infarction (lT2MI). Major adverse cardiac events (MACEs) including acute myocardial infarction, AHF (both only from day 3 to avoid inclusion bias), life-threatening arrhythmia, and cardiovascular death as well as all-cause death were assessed during 1-year follow-up. Among 7754 patients (age 45-98 years, 45% women), PMI occurred in 1016 (13.1%). At least one MACE occurred in 684/7754 patients (8.8%) and 818/7754 patients died (10.5%) within 1 year. Outcomes differed starkly according to aetiology: in patients with extra-cardiac PMI, T1MI, tachyarrhythmia, AHF, and lT2MI 51%, 41%, 57%, 64%, and 25% had MACE, and 38%, 27%, 40%, 49%, and 17% patients died within 1 year, respectively, compared to 7% and 9% in patients without PMI. These associations persisted in multivariable analysis. CONCLUSION: At 1 year, most PMI aetiologies have unacceptably high rates of MACE and all-cause death, highlighting the urgent need for more intensive treatments. STUDY REGISTRATION: https://clinicaltrials.gov/ct2/show/NCT02573532.

The Role of HbA1c as a Positive Perioperative Predictor of Surgical Site and Other Postoperative Infections: An Explorative Analysis in Patients Undergoing Minor to Major Surgery.

BACKGROUND: Patients with diabetes mellitus type 2 (DM2) inhere impaired peripheral insulin action leading to higher perioperative morbidity and mortality rates, with hospital-acquired infections being one important complication. This post hoc, observational study aimed to analyze the impact of surgical and metabolic stress as defined by the surrogate marker hemoglobin A1c (HbA1c), in relation to self-reported DM2, on perioperative infection rates in a subcohort of the Surgical Site Infection (SSI) Trial population. METHODS: All patients of the SSI study were screened for HbA1c levels measured perioperatively for elective or emergency surgery and classified according to the American Diabetes Association HbA1c cutoff values. SSI and nosocomial infections, self-reported state of DM2 and type of surgery (minor, major) were assessed. RESULTS: HbA1c levels were measured in 139 of 5175 patients (2.7%) of the complete SSI study group. Seventy patients (50.4%) self-reported DM2, while 69 (49.6%) self-reported to be non-diabetic. HbA1c levels indicating pre-diabetes were found in 48 patients (34.5%) and diabetic state in 64 patients (46%). Forty-five patients of the group self-reporting no diabetes (65.2%) were previously unaware of their metabolic derangement (35 pre-diabetic and 10 diabetic). Eighteen infections were detected. Most infections (17 of 18 events) were found in patients with HbA1c levels indicating pre-/diabetic state. The odds for an infection was 3.9-fold (95% CI 1.4 to 11.3) higher for patients undergoing major compared to minor interventions. The highest percentage of infections (38.5%) was found in the group of patients with an undiagnosed pre-/diabetic state undergoing major surgery. CONCLUSIONS: These results encourage investment in further studies evaluating a more generous and specific use of HbA1c screening in patients without self-reported diabetes undergoing major surgery. Trial registration Clinicaltrials.gov identifier: NCT01790529.

Temporary Extracorporeal Femoro-Femoral Crossover Bypass to Treat Acute Limb Ischemia due to Occlusive Femoral Transaortic Microaxial Left Ventricular Assist Device - A Novel Technique and Case Series.

BACKGROUND: The Impella transaortic microaxial left ventricular assist device (MLVAD) bears the risk of severe ipsilateral limb ischemia due to its percutaneous insertion through the common femoral artery (CFA). As long as the MLVAD is required for cardio - circulatory support, treatment options are limited. Therefore, we developed a temporary extracorporeal femoral - femoral crossover bypass to restore and maintain perfusion of the affected leg. METHODS: From October 2018, we treated all patients with severe limb ischemia due to the MLAVD with a femoral - femoral crossover bypass. For comparison, a consecutive cohort of patients undergoing placement of the MLAVD between January 2011 and October 2018 was identified. The primary outcome is the feasibility and safety of our percutaneously established extracorporeal femoral - femoral crossover bypass. RESULTS: Between January 2011 and July 2019, 25 of 245 (10.3%) patients developed a severe ipsilateral limb ischemia following the MLVAD placement. Until October 2018, 20 patients were treated conventionally (C - cohort) and since October 2018, five (consecutive) patients have been treated by an extracorporeal femoral - femoral cross over bypass (BP - Cohort). Following the BP - procedure, an immediate improvement of the perfusion was seen in all patients. Limb salvage was documented in 100% of our patients and 30 - day mortality was 60% in both groups. CONCLUSION: This is the first case series reporting on this novel technique. We demonstrated that the percutaneous creation of an extracorporeal crossover bypass is feasible, safe and effective and should therefore be promoted.

Adherence to the European Society of Cardiology/European Society of Anaesthesiology recommendations on preoperative cardiac testing and association with positive results and cardiac events: a cohort study.

BACKGROUND: European Society of Cardiology/European Society of Anaesthesiology (ESC/ESA) guidelines inform cardiac workup before noncardiac surgery based on an algorithm. Our primary hypotheses were that there would be associations between (i) the groups stratified according to the algorithms and major adverse cardiac events (MACE), and (ii) over- and underuse of cardiac testing and MACE. METHODS: This is a secondary analysis of a multicentre prospective cohort. Major adverse cardiac events were a composite of cardiac death, myocardial infarction, acute heart failure, and life-threatening arrhythmia at 30 days. For each cardiac test, pathological findings were defined a priori. We used multivariable logistic regression to measure associations. RESULTS: We registered 359 MACE at 30 days amongst 6976 patients; classification in a higher-risk group using the ESC/ESA algorithm was associated with 30-day MACE; however, discrimination of the ESC/ESA algorithms for 30-day MACE was modest; area under the curve 0.64 (95% confidence interval: 0.61-0.67). After adjustment for sex, age, and ASA physical status, discrimination was 0.72 (0.70-0.75). Overuse or underuse of cardiac tests were not consistently associated with MACE. There was no independent association between test recommendation class and pathological findings (P=0.14 for stress imaging; P=0.35 for transthoracic echocardiography; P=0.52 for coronary angiography). CONCLUSIONS: Discrimination for MACE using the ESC/ESA guidelines algorithms was limited. Overuse or underuse of cardiac tests was not consistently associated with cardiovascular events. The recommendation class of preoperative cardiac tests did not influence their yield. CLINICAL TRIAL REGISTRATION: NCT02573532.

Perioperative major adverse cardiac events in urgent femoral artery repair after coronary stenting are less common than previously reported.

OBJECTIVE: Noncardiac surgery early after coronary stenting has been associated with a high rate of stent thrombosis and catastrophic outcomes. However, those outcomes were mostly seen when dual antiplatelet therapy (DAPT) was discontinued before surgery. This observational study sought to estimate the risk of major adverse cardiac events (MACEs) after femoral artery repair following recent stent-percutaneous coronary intervention under continued DAPT and to explore potential risk factors. We suspect that in this setting, the risk of MACEs is lower than previously reported. METHODS: This retrospective cohort study included all consecutive patients who underwent femoral artery repair because of puncture site complications (bleeding or occlusion) within 28 days after coronary stenting at a tertiary referral center in Switzerland from 2005 to 2015. The primary end point consisted of the MACEs death, cardiac arrest, stent thrombosis, and myocardial infarction. RESULTS: There were 12,960 patients who underwent coronary stenting. Seventy patients (0.5%) required repair of the femoral vessels, which was performed under continued DAPT in all cases. Eight patients (11.4%; 95% confidence interval [CI], 5.4-21.8) experienced a total of 17 MACEs within 30 days after surgery, including 5 deaths (7.1%; 95% CI, 2.7-16.6). Factors significantly associated with postoperative MACEs were cardiogenic shock on admission before coronary stenting (hazard ratio, 6.9; 95% CI, 1.8-29.6; P = .035) and limb ischemia as an indication for surgery compared with bleeding (hazard ratio, 10.5; 95% CI, 2.7-40.7; P = .008). CONCLUSIONS: In our series, femoral artery repair under DAPT for access site complications early after stent-percutaneous coronary intervention is associated with only a modest MACE rate and therefore a much better outcome than previously reported.

Expression of RET is associated with Oestrogen receptor expression but lacks prognostic significance in breast cancer.

BACKGROUND: The Rearranged during Transfection (RET) protein is overexpressed in a subset of Estrogen Receptor (ER) positive breast cancer, with both signalling pathways functionally interacting. This cross-talk plays a pivotal role in the resistance of breast cancer cells to anti-endocrine therapies, and RET expression is assumed to correlate with poor prognosis based on findings in small patient cohorts. The aim of our study was to investigate the impact of RET expression on patient outcome in human breast cancer. METHODS: We performed an immunohistochemical analysis of RET protein expression on a tissue microarray encompassing 990 breast cancer patients and correlated its expression with clinicopathological parameters and survival data. RESULTS: Expression of RET was detected in 409 out of 990 cases (41.3%). RET and ER expression significantly correlated (p < 0.0001). The Luminal B HER2-positive subtype showed the highest expression rate (48.9%). In univariate and multivariate survival analyses, RET expression had no impact on overall survival. CONCLUSION: We confirmed the co-expression of RET and ER, but we did not find RET expression to be an independent prognostic factor in human breast cancer. Clinical trials with newly developed RET inhibitors are needed to evaluate if RET inhibition has a beneficial impact on patient survival in ER positive breast cancer.

Antimicrobial Prophylaxis Redosing Reduces Surgical Site Infection Risk in Prolonged Duration Surgery Irrespective of Its Timing.

BACKGROUND: Long-duration surgery requires repeated administration of antimicrobial prophylaxis (amp). Amp "redosing" reduces incidence of surgical site infections (SSI) but is frequently omitted. Clinical relevance of redosing timing needs to be investigated. Here, we evaluated the effects of compliance with amp redosing and its timing on SSI incidence in prolonged duration surgery. METHODS: Data from >9000 patients undergoing visceral, trauma, or vascular surgery with elective or emergency treatment in two tertiary referral Swiss hospitals were analyzed. All patients had to receive amp preoperatively and redosing, if indicated. Antibiotics used were cefuroxime (1.5 or 3 g, if weight >80 kg), or cefuroxime and metronidazole (1.5 and 0.5 g, or 3 and 1 g doses, if weight >80 kg). Alternatively, in cases of known or suspected allergies, vancomycin (1 g), gentamicin (4 mg/Kg), and metronidazole or clindamycin (300 mg) with or without ciprofloxacin (400 mg) were used. Association of defined parameters, including wound class, ASA scores, and duration of operation, with SSI incidence was explored. RESULTS: In the whole cohort, SSI incidence significantly correlated with duration of surgery (ρ = 0.73, p = 0.031). In 593 patients undergoing >240 min long interventions, duration of surgery was the only parameter significantly (p < 0.001) associated with increased SSI risk, whereas wound class, ASA scores, treatment areas, and emergency versus elective hospital entry were not. Redosing significantly reduced SSI incidence as shown by multivariate analysis (OR 0.60, 95% CI 0.37-0.96, p = 0.034), but exact timing had no significant impact. CONCLUSIONS: Long-duration surgery associates with higher SSI incidence. Irrespective of its exact timing, amp redosing significantly decreases SSI risk.

Associations of Hospital Length of Stay with Surgical Site Infections.

BACKGROUND: Surgical site infections (SSI) are a major cause of morbidity and mortality in surgical patients. Postoperative and total hospital length of stay (LOS) are known to be prolonged by the occurrence of SSI. Preoperative LOS may increase the risk of SSI. This study aims at identifying the associations of pre- and postoperative LOS in hospital and intensive care with the occurrence of SSI. METHODS: This observational cohort study includes general, orthopedic trauma and vascular surgery patients at two tertiary referral centers in Switzerland between February 2013 and August 2015. The outcome of interest was the 30-day SSI rate. RESULTS: We included 4596 patients, 234 of whom (5.1%) experienced SSI. Being admitted at least 1 day before surgery compared to same-day surgery was associated with a significant increase in the odds of SSI in univariate analysis (OR 1.65, 95% CI 1.25-2.21, p < 0.001). More than 1 day compared to 1 day of preoperative hospital stay did not further increase the odds of SSI (OR 1.08, 95% CI 0.77-1.50, p = 0.658). Preoperative admission to an intensive care unit (ICU) increased the odds of SSI as compared to hospital admission outside of an ICU (OR 2.19, 95% CI 0.89-4.59, p = 0.057). Adjusting for potential confounders in multivariable analysis weakened the effects of both preoperative admission to hospital (OR 1.38, 95% CI 0.99-1.93, p = 0.061) and to the ICU (OR 1.89, 95% CI 0.73-4.24, p = 0.149). CONCLUSION: There was no significant independent association between preoperative length of stay and risk of SSI while SSI and postoperative LOS were significantly associated.

[Aortic aneurysms - epidemiology and therapeutic options]. / Das Aortenaneurysma ­ Epidemiologie und therapeutische Optionen.

Aortic aneurysms - epidemiology and therapeutic options Abstract. Aortic aneurysms can arise in any part of the aorta between its root and its bifurcation. Men over the age of 65 are most commonly affected while the prevalence increases with age. Risk factors are identical with those for any atherosclerotic disease. Treatment is always invasive while its indication depends on the expected risk of rupture (which in turn depends on the maximum diameter) and the risk of the treatment itself. While perioperative mortality rates are significantly lower after endovascular than after open aneurysm repair, long-term mortality rates are not.

Free Flaps in Patients with Advanced Arteriosclerosis of the Tibial Vessels: Mini Vein Graft to the Peroneal Artery.

Lower extremity reconstruction with free flaps in patients with only peroneal artery runoff remains a challenge. Here, we present a novel technique for reconstruction of medial defects in the distal leg using a medial approach to the peroneal artery and a short interposition vein graft anastomosed end to side to the peroneal artery. A retrospective, single-center study was performed including all patients who underwent lower extremity reconstruction with free flaps anastomosed to the peroneal artery using a mini vein graft from November 2020 to March 2022. The primary outcome measure was limb salvage. Secondary endpoints were flap survival and postoperative complications. Seven patients received lower extremity free flap reconstruction with a mini vein graft to the peroneal artery. Flap loss rate was 0%. Limb salvage was achieved in five patients (71%). At 6-month follow-up, all patients were ambulatory. One patient died 1 month after surgery due to heart failure. Mini vein graft to the peroneal artery allows reliable and safe free flap reconstruction of distal leg defects in patients with only peroneal artery runoff.

Impact of an intensive 2-day endovascular training course on technical performance of trainees.

BACKGROUND: The objective of this study was to evaluate the effect of a 2-day international endovascular training course on the performance of trainees as compared with a control group, assessed in a bench model-based task using an objective structured evaluation protocol. METHODS: A total of 50 trainees, 28 course participants of 2 consecutive identical courses and a control group of 22 participants with a similar level of experience without course attendance, underwent baseline and final assessment (simulated arterial access task). The evaluation form consisted of a global assessment (GA), task-specific checklist percentage score (CL), and global rating scale percentage score (GR), with both percentage scores ranging from 0% (worst performance) to 100% (best performance). RESULTS: Course participants were more likely to pass the GA at final testing than the control group (odds ratio=59; 95% confidence interval [CI] 9.5-656; P<0.001). The estimated difference in percentage score at final testing between course participants and the control group was 26% (95% CI 18-34; P<0.001) for the CL and 29% (95% CI 19-40; P<0.001) for the GR. CONCLUSIONS: A 2-day structured endovascular training course significantly improves endovascular performance in a simulated environment. These results are important for the design of endovascular training curricula with the ultimate goal of contributing to patient safety.

A Novel Percutaneous Technique for Aorto-Iliac Thrombectomy without the Risk of Embolization.

Classic surgical thrombectomy of the aorta and iliac arteries through an incision in the groin vessels harbors the risk of embolization to the viscero-renal as well as hypogastric arteries, while percutaneous endovascular thrombectomy techniques can lead to peripheral embolization to the lower limbs. Therefore, we describe a novel, percutaneous technique that tackles the above issues. Furthermore, we also present our initial experience using the technique. The principle of the technique is to percutaneously place large-bore sheaths in the iliac arteries that deliberately occlude the latter to protect the lower limbs from embolization. Through one of these sheaths, over wire Fogarty® catheters can be placed and inflated in the ostia of the coeliac trunk, superior mesenteric artery, renal arteries, and hypogastric arteries as needed. A large thrombectomy balloon catheter is then used to bring any aorto-iliac thrombus into the sheaths, whereafter the thrombus is removed from the sheaths by simply deflating their valves. Additional endovascular procedures of the aorto-iliac branches can be performed as needed. We report nine procedures in 8 patients (4 males and 4 females) with a median age of 63 (53-68.5). Additional endovascular procedures were performed in 6 (66.7%) procedures. All but one procedure were technically successful, and all patients had palpable foot pulses on completion of the procedures, while no patient had clinical signs of peripheral embolization. This technique is a very valid addition to the vascular surgeon's armamentarium when treating aorto-iliac thrombotic events because it is minimally invasive while still protecting against embolization and offering the flexibility to perform a wide range of additional endovascular procedures where needed.

Multimodality imaging and 3D-printing of a thoraco-abdominal aortic aneurysm eroding into the spine.

A rare case of a previously treated thoraco-abdominal aortic aneurysm eroding into the thoracic spine is described. Initially, several follow-up CT angiography scans showed an increasing aneurysm sack, but no endoleak could be depicted. Then, a new rapidly developing erosion into the thoracic spine was noted. MRI imaging excluded any other underlying infectious or malignant process. Additional contrast-enhanced ultrasound excluded an endoleak. A 3D-printed model of the aneurysm and spine and cinematic renderings were created to improve visualization. She underwent relining of the thoracic stent graft. Follow-up imaging showed a stable aneurysm size and no progression of the vertebral erosions.

Prediction of perioperative myocardial infarction/injury in high-risk patients after noncardiac surgery.

AIMS: Perioperative myocardial infarction/injury (PMI) is a surprisingly common yet difficult-to-predict cardiac complication in patients undergoing noncardiac surgery. We aimed to assess the incremental value of preoperative cardiac troponin (cTn) concentration in the prediction of PMI. METHODS AND RESULTS: Among prospectively recruited patients at high cardiovascular risk (age ≥65 years or ≥45 years with preexisting cardiovascular disease), PMI was defined as an absolute increase in high-sensitivity cTnT (hs-cTnT) concentration of ≥14 ng/L (the 99th percentile) above the preoperative concentration. Perioperative myocardial infarction/injury was centrally adjudicated by two independent cardiologists using serial measurements of hs-cTnT. Using logistic regression, three models were derived: Model 1 including patient- and procedure-related information, Model 2 adding routinely available laboratory values, and Model 3 further adding preoperative hs-cTnT concentration. Models were also compared vs. preoperative hs-cTnT alone. The findings were validated in two independent cohorts. Among 6944 patients, PMI occurred in 1058 patients (15.2%). The predictive accuracy as quantified by the area under the receiver operating characteristic curve was 0.73 [95% confidence interval (CI) 0.71-0.74] for Model 1, 0.75 (95% CI 0.74-0.77) for Model 2, 0.79 (95% CI 0.77-0.80) for Model 3, and 0.74 for hs-cTnT alone. Model 3 included 10 preoperative variables: age, body mass index, known coronary artery disease, metabolic equivalent >4, risk of surgery, emergency surgery, planned duration of surgery, haemoglobin, platelet count, and hs-cTnT. These findings were confirmed in both independent validation cohorts (n = 722 and n = 966). CONCLUSION: Preoperative cTn adds incremental value above patient- and procedure-related variables as well as routine laboratory variables in the prediction of PMI.

FACS-purified myoblasts producing controlled VEGF levels induce safe and stable angiogenesis in chronic hind limb ischemia.

We recently developed a method to control the in vivo distribution of vascular endothelial growth factor (VEGF) by high throughput Fluorescence-Activated Cell Sorting (FACS) purification of transduced progenitors such that they homogeneously express specific VEGF levels. Here we investigated the long-term safety of this method in chronic hind limb ischemia in nude rats. Primary myoblasts were transduced to co-express rat VEGF-A(164) (rVEGF) and truncated ratCD8a, the latter serving as a FACS-quantifiable surface marker. Based on the CD8 fluorescence of a reference clonal population, which expressed the desired VEGF level, cells producing similar VEGF levels were sorted from the primary population, which contained cells with very heterogeneous VEGF levels. One week after ischemia induction, 12 × 10(6) cells were implanted in the thigh muscles. Unsorted myoblasts caused angioma-like structures, whereas purified cells only induced normal capillaries that were stable after 3 months. Vessel density was doubled in engrafted areas, but only approximately 0.1% of muscle volume showed cell engraftment, explaining why no increase in total blood flow was observed. In conclusion, the use of FACS-purified myoblasts granted the cell-by-cell control of VEGF expression levels, which ensured long-term safety in a model of chronic ischemia. Based on these results, the total number of implanted cells required to achieve efficacy will need to be determined before a clinical application.

Therapeutic arteriogenesis by factor-decorated fibrin matrices promotes wound healing in diabetic mice.

Chronic wounds in type-2 diabetic patients present areas of severe local skin ischemia despite mostly normal blood flow in deeper large arteries. Therefore, restoration of blood perfusion requires the opening of arterial connections from the deep vessels to the superficial skin layer, that is, arteriogenesis. Arteriogenesis is regulated differently from microvascular angiogenesis and is optimally stimulated by high doses of Vascular Endothelial Growth Factor-A (VEGF) together with Platelet-Derived Growth Factor-BB (PDGF-BB). Here we found that fibrin hydrogels decorated with engineered versions of VEGF and PDGF-BB proteins, to ensure protection from degradation and controlled delivery, efficiently accelerated wound closure in diabetic and obese db/db mice, promoting robust microvascular growth and a marked increase in feeding arterioles. Notably, targeting the arteriogenic factors to the intact arterio-venous networks in the dermis around the wound was more effective than the routine treatment of the inflamed wound bed. This approach is readily translatable to a clinical setting.