Chris Klonaris

Propofol: A review of its non-anaesthetic effects

Propofol, a short-acting intravenous anaesthetic agent has gained wide acceptance since its introduction in the late 80s, not only in operating rooms but also in other departments, due to its several advantages. Apart from its multiple anaesthetic advantages, it has been reported recently that propofol exerts a number of non-anaesthetic effects. The drug stimulates constitutive nitric oxide (NO) production and inhibits inducible NO production. Propofol has also anxiolytic properties, which may be related to several neuromediator systems. Moreover, it has antioxidant, immunomodulatory, analgesic, antiemetic and neuroprotective effects. Furthermore, propofol inhibits both platelet aggregation and intracellular calcium increases in response to thrombin or ADP and it also exerts direct inhibitory effects on recombinant cardiac sarcolemmal KATP channels. All these beneficial properties may expand propofols clinical use.

Comparison of outcomes with open, fenestrated, and chimney graft repair of juxtarenal aneurysms: are we ready for a paradigm shift?

Purpose To review the literature reporting open surgical and endovascular treatment of juxtarenal aortic aneurysm (JAA). Methods A systematic search of the PubMed database was carried out to identify English-language articles published between January 2001 and July 2012 on the management of JAA with open surgery, fenestrated endovascular aneurysm repair (F-EVAR), and the chimney graft technique (Ch-EVAR). The search found 20 studies with a total of 1725 patients (76% men; age range 66–74 years) undergoing open surgery, 10 studies detailing 931 patients (87.6% men; age range 72–75 years) receiving F-EVAR, and 5 studies comprising 94 patients (75% men; age range 68–82) reporting Ch-EVAR. Results A total of 2465 vessels were targeted with fenestrations and 151 with chimney grafts (CG); intraoperative target vessel preservation was 98.6% and 98.0%, respectively. Cumulative 30-day mortality was 3.4%, 2.4%, and 5.3% for open surgery, F-EVAR and Ch-EVAR, respectively (p=NS). Impaired renal function was noted in 18.5%, 9.8%, and 12% following open surgery, F-EVAR, and Ch-EVAR, respectively (open vs. F-EVAR: p<0.001). New-onset dialysis was required postoperatively in 3.9%, 1.5%, and 2.1%, respectively (open vs. F-EVAR: p<0.001). Postoperative cardiac complications were noted in 11.3%, 3.7%, and 7.4%, respectively (open vs. F-EVAR: p<0.001). The incidence of ischemic stroke was 0.1% and 0.3% following open surgery and F-EVAR, but 3.2% after Ch-EVAR (open vs. Ch-EVAR: p=0.002; F-EVAR vs. Ch-EVAR: p=0.012). Early proximal type I endoleak was lower after F-EVAR compared to Ch-EVAR (4.3% vs. 10%, respectively, p=0.002). Conclusion Open surgery remains a safe and effective treatment option for good risk patients with JAA. F-EVAR is associated with low operative mortality, compares favorably to open surgery in terms of morbidity, and current midterm data indicate that it can be a valid treatment option in both low- and high-risk patients. Early results of Ch-EVAR demonstrate feasibility only. In view of the limited number of reports and the lack of long-term data, the technique should be considered only in acute poor surgical risk patients, as a bailout in case of unintentional renal artery coverage, or in elective poor surgical cases that are not suitable for F-EVAR.

Primary stenting for aortic lesions: From single stenoses to total aortoiliac occlusions

PURPOSE This study evaluated the feasibility, safety, and efficacy of primary stenting in atherosclerotic stenoses and occlusions of the infrarenal aorta. METHODS Between January 2003 and December 2006, 12 patients (6 men) with a mean age of 66.3 +/- 4.1 years who had infrarenal aortic occlusive disease were treated with primary stenting (aortic stenosis, 8; chronic total aortobiiliac occlusion, 4). Reasons for referral were severe claudication in six patients (50%), ischemic rest pain in four (33.3%), and minor tissue loss in two (16.7%). Three patients (25%) had chronic renal failure and were on dialysis. Follow-up was performed in all 12 patients. RESULTS Technical success was 91.7% because one patient had a residual stenosis >30% after stent placement and balloon postdilation owing to severe calcification of the aorta. However, clinical and immediate hemodynamic success was achieved in all 12 patients (100%). The preprocedural mean resting ankle-brachial index (ABI) values of 0.56 +/- 0.13 at the right side and 0.59 +/- 0.15 at the left were increased to 0.97 +/- 0.04 and 0.95 +/- 0.06, respectively, after treatment (P < .01). At the end of the mean follow-up of 18.3 months (range, 6-37 months), the primary clinical and hemodynamic patency was 91.7% +/- 7.98%, and the mean resting ABI values were 0.96 +/- 0.04 for the right and 0.92 +/- 0.1 for the left side (P < .01 compared with preinterventional values). None of the patients in the study underwent reintervention. An access-related groin hematoma developed in one patient, but no other major or minor complications occurred. One patient died 8 months after the procedure of chronic renal failure complications. CONCLUSION Primary stenting is feasible, safe, and effective for the whole spectrum of aortic occlusive disease. Especially for patients with infrarenal aortic stenoses, it is recommended as the first-line treatment and should be considered as a viable alternative to surgery for total aortoiliac occlusions.

Late open conversion after failed endovascular aortic aneurysm repair

OBJECTIVE Endovascular aortic aneurysm repair (EVAR) is widely used for the treatment of abdominal aortic aneurysms. Complications secondary to EVAR are also treated with endovascular techniques. When this is not applicable, open surgical repair is mandatory. This study aims to present our experience in open surgical repair after failed EVAR. METHODS Within the period from 2004 through 2013, 18 patients (17 men; mean age, 73.9 years) were operated on because of EVAR failure due to persistent type II endoleak (n = 10), type I or III endoleak (n = 3), mixed-type endoleaks (n = 2), stent graft thrombosis (n = 2), and aortoenteric fistulae (n = 1). Stent grafts used for EVAR were Zenith (n = 8), Talent (n = 4), Excluder (n = 4), and Anaconda (n = 2). RESULTS Mean time interval between EVAR and open conversion was 36 months (range, 2-120 months). Fifteen (83.3%) operations were elective, and three (16.7%) were urgent due to aneurysm rupture (n = 2) and aortoenteric fistula (n = 1). Six (33.3%) patients with type II endoleak were treated with simple ligation of the culprit vessels, without aortic clamping and stent graft explantation. In six (33.3%) patients, the stent graft was partially removed except from the segment attached to the proximal neck, while in five (27.8%) patients, complete removal of the stent graft was necessary. Finally, in one patient, with type III endoleak, a hybrid endovascular and open repair was performed. Clamping of the aorta was necessary in 12 (66.7%) patients (infrarenal, n = 10 or suprarenal, n = 2). Overall operative mortality was 5.6%. Postoperative complications included one abdominal wall defect requiring surgical revision and paroxysmal atrial fibrillation both in the same patient, and one case of pulmonary infection, requiring prolonged intubation and intensive care unit stay for 6 days. CONCLUSIONS Late open conversion after failed EVAR remains challenging. Avoidance of aortic cross-clamping and if possible, partial or total preservation of the stent graft may improve outcomes in terms of operative mortality and morbidity. Elective operations seem to be associated with better outcomes, prompting thus for close follow-up of EVAR patients and early decision for conversion if other options are doubtful.

Hybrid repair of ruptured infected anastomotic femoral pseudoaneurysms: Emergent stent-graft implantation and secondary surgical debridement

BACKGROUND Rupture of infected anastomotic femoral artery pseudoaneurysms (AFAPs) represents a limb and life-threatening condition requiring emergency intervention. This study aimed to evaluate the feasibility, safety, and efficacy of a hybrid repair for ruptured infected AFAPs consisted of percutaneous stent-graft deployment and second-stage surgical debridement. METHODS Between October 2004 and January 2008, 6 patients (3 female, mean age 65.8 +/- 11.4 years) with ruptured infected AFAPs were treated with emergent percutaneous stent-graft implantation and secondary surgical debridement. Three patients had undergone a femoro-popliteal and 1 a femoro-tibial bypass for peripheral arterial disease, while 2 patients had a femoral arteriovenous graft (AVG) for hemodialysis access due to chronic renal failure. Four pseudoaneurysms were located at the common femoral artery (CFA) and 2 involved the superficial femoral artery (SFA). Mean pseudoaneurysm diameter was 6.8 +/- 0.9 mm (range, 5.4-7.8 mm). The mean interval between the initial operation and presentation to our department was 26.7 +/- 14.5 months (range, 7-50 months). All patients suffered from severe comorbidities and were judged unfit for major surgery under general anesthesia. RESULTS All patients were successfully managed by urgent percutaneous deployment of covered stents at the site of the arterial deficit. Extensive surgical debridement along with pseudoaneurysm excision was accomplished successfully in all 6 patients 1-3 days after stent-graft placement under local anesthesia, without the need for extended vessel exposure for proximal and distal control. No death occurred within 30 days after stent-graft implantation. During follow-up, (mean 14.1 +/- 8.2 months, range, 6 to 25 months) all stent-grafts remained patent without endoleak, while no signs of recurrent local or systemic infection were noticed. Two patients died at 8 and 10 months after the procedure due to heart failure complications and acute myocardial infarction, respectively. CONCLUSION Emergency stent-graft deployment, followed by secondary surgical debridement and long-term antimicrobial therapy is a viable alternative for ruptured infected AFAPs. Especially for patients unfit for major surgery, it may be the most favorable treatment option.

Clinical implication of plasma neutrophil gelatinase-associated lipocalin (NGAL) concentrations in patients with advanced carotid atherosclerosis

Abstract Background: Neutrophil gelatinase-associated lipocalin (NGAL) is well established as an early and specific biomarker of kidney disease. Recent evidence further suggests that NGAL may play a crucial role in vascular remodeling and plaque instability during the development of atherosclerosis. Methods: Plasma NGAL concentrations measured using a solid-phase enzyme-linked immunosorbent assay (ELISA) were correlated with medical history, risk factors and medication intake in 141 patients with advanced carotid atherosclerotic lesions who underwent carotid endarterectomy for vascular repair. Results: Plasma NGAL concentrations were associated with patient age (Rs=0.2055, p=0.0144), plasma homocysteine (Rs=0.4274, p<0.00001) and serum creatinine (Rs=0.4640, p<0.00001) concentrations and estimated glomerular filtration rate (eGFR) (Rs=−0.4911, p<0.00001). Hypertensive patients, as well as those receiving therapy with angiotensin converting enzyme (ACE) inhibitors, presented with significantly enhanced plasma NGAL concentrations when compared to normotensive (p=0.0341) patients and those not treated (p=0.0004). Enhanced NGAL concentrations did not meet statistical significance for patients with advanced stenosis grade (p=0.0971) or a history of peripheral artery disease (p=0.0827). Multiple regression analysis identified homocysteine, creatinine, eGFR and treatment with ACE inhibitors (p=0.0019, <0.00001, 0.0005 and 0.0219, respectively) as independent predictors of NGAL concentration. Conclusions: Plasma NGAL concentrations were associated with patient age, hypertension, eGFR, creatinine and homocysteine concentrations and therapy with ACE inhibitors. The role of NGAL in the development of atherosclerosis needs to be further explored taking into consideration the uncontrolled effect of renal disease in atherosclerotic patients with multiple risk factors. Clin Chem Lab Med 2010;48:1035–41.

Emergency Stenting of a Ruptured Infected Anastomotic Femoral Pseudoaneurysm

A 74-year-old man presented with a ruptured infected anastomotic femoral pseudoaneurysm. Due to severe medical comorbidities he was considered unsuitable for conventional surgical management and underwent an emergency endovascular repair with a balloon-expandable covered stent. The pseudoaneurysm was excluded successfully and the patient had an uneventful postoperative recovery with long-term suppressive antimicrobials. He remained well for 10 months after the procedure with no signs of recurrent local or systemic infection and finally died from an acute myocardial infarction. To our knowledge, emergency endovascular treatment of a free ruptured bleeding femoral artery pseudoaneurysm has not been documented before in the English literature. This case illustrates that endovascular therapy may be a safe and efficient alternative in the emergent management of ruptured infected anastomotic femoral artery pseudoaneurysms when traditional open surgery is contraindicated.

Telomerase expression on aortic wall endothelial cells is attenuated in abdominal aortic aneurysms compared to healthy nonaneurysmal aortas

OBJECTIVE Linear chromosomes carry specific DNA structures at their ends called telomeres. The latter shorten with each successive cell division making their length a marker of cell age. Telomerase prevents such telomere attrition by adding back telomeric repeats at the telomere ends, thus playing an important role in cell aging. On the other hand, an abdominal aortic aneurysm (AAA) represents an age-related degenerative disorder. The aim of the present study was to investigate a potential correlation of telomerase expression with AAA formation. METHODS Aortic wall tissue samples were collected from 49 patients (mean age, 63.8 ± 4.4 years) with AAAs during open elective repair and from 24 deceased organ donors as controls (mean age, 60.5 ± 3.9 years). Telomerase expression on endothelial cells was detected by immunohistochemistry. Associations of telomerase positivity with AAAs and epidemiologic and clinical variables were investigated. RESULTS Telomerase expression was significantly decreased in patients with AAAs (11 of 49; 22.4%) compared to controls (19 of 24; 79.2%; P < .001). This association persisted after adjustment for age, gender, coronary artery disease (CAD), hypercholesterolemia, hypertension and smoking (odds ratio, 0.47; 95% confidence interval, 0.14-0.58; P < .01.). CONCLUSION Patients with AAAs have attenuated telomerase endothelial expression compared to controls, implying a protective role of telomerase against AAA formation. Further investigation of pathways involved in vascular aging may contribute to elucidation of AAA pathogenetic mechanisms.

Toll-Like Receptor 4 Immunohistochemical Expression Is Enhanced in Macrophages of Symptomatic Carotid Atherosclerotic Plaques

Background: A growing body of evidence supports a role for Toll-like receptor 4 (TLR4), a primary receptor of the innate immune system, in atherosclerosis initiation and progression. Carotid atheroma macrophages (MACs) and smooth muscle cells (SMCs) express TLR4; nevertheless, correlations with epidemiological and clinical variables and especially cerebrovascular symptomatology remain unsettled. Methods: Carotid atherosclerotic plaques were obtained by standard carotid endarterectomy on 157 patients with carotid artery disease (84 asymptomatic – 73 symptomatic). TLR4 expression in MACs and SMCs of carotid atheroma was detected by immunohistochemistry techniques. TLR4 positivity, overexpression and intensity of immunostaining in MACs and SMCs were correlated with cerebrovascular symptomatology, epidemiological and clinical variables. Results: MAC TLR4 positivity was noted in 129 (82.2%) patients. Patients receiving statins had significantly lower TLR4 expression. Rates of MAC TLR4 positivity were higher among symptomatic patients (odds ratio, OR = 5.1; 95% confidence interval, CI = 1.8–14.3; p < 0.001); the association was stronger for transient ischemic attacks. TLR4 overexpression was also significantly enhanced among symptomatic patients (OR = 2.3; 95% CI = 1.02–5.03; p < 0.05). No correlations were detected between SMC TLR4 expression and cerebrovascular symptoms. In multivariate models adjusting for age, gender, body mass index, hyperlipidemia and smoking, MAC TLR4 positivity was associated with a cerebrovascular event during the last 6 months (OR = 4; 95% CI = 1.2–13.3; p = 0.02). Conclusions: Symptomatic carotid artery plaques are characterized by increased expression of TLR4 in macrophages supporting a potential role for TLR4 in the pathophysiology and clinical presentation of cerebrovascular disease. Further investigation is warranted.

Endovascular repair of a persistent sciatic artery aneurysm.

Persistent sciatic artery (PSA), a persistent embryologic continuation of the internal iliac artery, represents a rare yet clinically important vascular anomaly. PSA is prone to aneurysmal change, which can subsequently lead to distal embolization, sciatic neuropathy, or rupture. The conventional surgical treatment of PSA aneurysms is commonly complex and carries the risk for sciatic nerve damage. We report herein the successful endovascular management of a PSA aneurysm and postaneurysmal stenosis with the use of two overlapping self-expanding stent-grafts via a contralateral transfemoral approach. Additionally, a review of the literature regarding the treatment of these unusual peripheral aneurysms is provided.