An investigation into the cytotoxic effects of microbubbles and their constituents on osteosarcoma and bone marrow stromal cells.

BACKGROUND: Ultrasound-responsive microbubbles offer a means of achieving minimally invasive, localised drug delivery in applications including regenerative medicine. To facilitate their use, however, it is important to determine any cytotoxic effects they or their constituents may have. The aim of this study was to test the hypothesis that phospholipid-shelled microbubbles are non-toxic to human bone-derived cells at biologically-relevant concentrations. METHODS: Microbubbles were fabricated using combinations of 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), 1,2-dibehenoyl-sn-glycero-3-phosphocholine (DBPC), polyoxyethylene(40) stearate (PEG40S) and 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[methoxy(polyethylene-glycol)-2000] (DSPE-PEG2000). Microbubble size and concentration were measured as a function of time and temperature by optical microscopy. Effects on MG63 osteosarcoma and human bone marrow stromal cells (BMSCs) were measured for up to 72 h by assay for viability, metabolic activity and proliferation. RESULTS: DBPC:DSPE-PEG2000 microbubbles were significantly more stable than DSPC:PEG40S microbubbles under all conditions tested. Serum-containing medium had no detrimental effect on microbubble stability, but storage at 37 °C compared to at 4 °C reduced stability for both preparations, with almost complete dissolution of microbubbles at times ≥24 h. DSPC:PEG40S microbubbles had greater inhibitory effects on cell metabolism and growth than DBPC:DSPE-PEG2000 microbubbles, with PEG40S found to be the principle inhibitory component. These effects were only evident at high microbubble concentrations (≥20% (v/v)) or with prolonged culture (≥24 h). Increasing cell-microbubble contact by inversion culture in a custom-built device had no inhibitory effect on metabolism. CONCLUSIONS: These data indicate that, over a broad range of concentrations and incubation times, DBPC:DSPE-PEG2000 and DSPC:PEG40S microbubbles have little effect on osteoblastic cell viability and growth, and that PEG40S is the principle inhibitory component in the formulations investigated.

Long-term results with the modified Sugiura procedure for the management of variceal bleeding: standing the test of time in the treatment of bleeding esophageal varices.

BACKGROUND: The surgical approaches to the treatment of bleeding esophageal varices in cirrhotic patients have been reduced since the clinical development of endoscopic sclerotherapy, transjugular intrahepatic portosystemic shunt (TIPS), and liver transplantation. However, when acute sclerotherapy fails, and in cases where no further treatment is accessible, emergency surgery may be life saving. In the present study we retrospectively analyzed the results of the modified Sugiura procedure, performed as emergency and semi-elective treatment in the patient with bleeding esophageal varices. METHODS: Ninety patients with cirrhosis and portal hypertension were managed in our department for variceal esophageal bleeding between January 1985 and December 1992. The modified Sugiura procedure was performed in 46 patients on an emergency (25 patients) or semi-elective (21 patients) basis. Liver cirrhosis stage according to Child classification was A in 4 patients, B in 16 patients, and C in 26 patients. RESULTS: Acute bleeding was controlled in all patients. Postoperative mortality was 23.9% (11 of 46 patients). The mortality rate was 34.6% in Child class C patients (9 of 26 patients), and 12.5% in Child class B patients (2 of 16 patients). Twenty-four patients had long-term follow-up extending from 14 months to 22 years (mean 83.1 months). Ten of 24 patients (41.6%) did not develop rebleeding for 5-22 years (mean 10.3 years). Overall 5-year survival in these 24 patients was 62.5%. CONCLUSIONS: The modified Sugiura procedure remains an effective rescue therapy for patients with bleeding esophageal varices when alternative treatments fail or are not indicated. Moreover, it can be a life-saving procedure in patients with anatomy unsuitable for shunt surgery or for patients treated in nonspecialized centers where surgical expertise for a shunt operation is not available.

Super-selective hepatic arterial infusions as established technique ('ARETAIEION' Protocol) of [177Lu]DOTA-TATE in inoperable neuroendocrine liver metastases of gastro-entero-pancreatic (GEP) tumors.

AIM: Aim of this study was to evaluate the effectiveness of non-carrier added (n. c. a.) [177Lu]DOTA-TATE in inoperable liver metastases, positive for sst2 receptor overexpression (verified by Octreoscan and confirmed by biopsy) due to neuroendocrine gastroenteropancreatic (GEP) tumors. [177Lu]DOTA-TATE has been infused after selective catheterization of the hepatic artery, minimising in parallel the toxicity of non-target tissues. METHODS: The dose per session administered to each patient (12 cases in total) was 7400 MBq (200 mCi). Repetitions did not exceed 6-fold with treatment intervals of 5-8 weeks. Response assessment was classified according to the therapeutic benefit. Absorbed doses delivered to metastases, kidneys and red marrow were calculated according to OLINDA 1.1 program and the derived values were correlated to the Response Evaluating Criteria in Solid Tumors (RECIST). CT/MRI scans were performed as baseline before, during and after the end of treatment and monthly ultrasound images for follow-up estimation and measurements. Toxicity (World Health Organization criteria) was measured using blood and urine tests of renal, hepatic and bone marrow function. RESULTS: None of the patients resulted complete response (0.0%); partial response was assessed in 8 (66.7%), disease stabilization in 3 (25%) and progressive disease in 1(8.3%). A 14-month median survival time was estimated for all patients, so far. Eight of 12 (66.7%) showed a mean target diameter shrinkage ranging from 33% to 45%. The organ average radiation dose estimation was found as follows: a) liver tumor 20.8 mGy/MBq; b) liver 0.14 mGy/MBq; c) kidneys 0.41 mGy/MBq; d) spleen 1.4 mGy/MBq; and f) bone marrow 0.022 mGy/MBq. The average absorbed dose per session to a tumor for a spherical mass of 20 g was estimated to be 20.8 mGy/MBq, depending on the histotype of the tumor. WHO toxicity grade 2 to 3 erythro-, leuko- and thrombo-cytopenia occurred in 9 (75%) cases observed about after the third session. CONCLUSION: In unresectable metastatic liver lesions positive for somatostatin receptors repeated, trans-hepatic high doses of [177Lu]DOTA-TATE resulted in a more than promising therapeutic outcome with a partial response in 75% of the treated patients. Given the loco-regional modality character of the administration technique, no nephro-toxicity has been so far observed whereas a remarkable myelotoxicity was noticed.

High bifurcation of the brachial artery.

Variations of the arterial pattern in the upper limb are quite common in humans. In the present study, we describe two cases of high bifurcation of the brachial artery. In the first cadaver both branches run superficially along the arm and were also located superficially at the antecubita fossa. In the second cadaver the branch that continues as the radial artery in the forearm run superficially and was located also superficially at the antecubita fossa, while the second branch had a more or less normal distribution. The embryological basis and clinical significance are discussed.

Renal angioplasty and stenting: is it still indicated after ASTRAL and STAR studies?

A renal artery stenosis (RAS) is common among patients with atherosclerosis, up to a third of patients undergoing cardiac catheterization. Fibromuscular dysplasia is the next cause of RAS, commonly found in young women. Atherosclerosis RAS generally progresses overtime and is often associated with loss of renal mass and worsening renal function (RF). Percutaneous renal artery stent placement is the preferred method of revascularization for hemodynamically significant RAS according to ACC and AHA guidelines. Several randomized trials have shown the superiority of endovascular procedures to medical therapy alone. However, two studies ASTRAL and STAR studies were recently published and did not find any difference between renal stenting and medical therapy. But these studies have a lot of limitations and flaws as we will discuss (poor indications, poor results, numerous complications, failures, poor technique, inexperienced operators, ecc.). Despite these questionable studies, renal stenting keeps indications in patients with: uncontrolled hypertension; ischemic nephropathy; cardiac disturbance syndrome (e.g. "flash" pulmonary edema, uncontrolled heart failure or uncontrolled angina pectoris); solitary kidney. To improve the clinical response rates, a better selection of the patients and lesions is mandatory with: good non-invasive or invasive imaging; physiologic lesion assessment using transluminal pressure gradients; measurements of biomarkers (e.g., BNP); fractional flow reserve study. A problem remains after renal angioplasty stenting, the deterioration of the RF in 20-30% of the patients. Atheroembolism seems to play an important role and is probably the main cause of this R.F deterioration. The use of protection devices alone or in combination with IIb IIa inhibitors has been proposed and seems promising as shown in different recent reports. Renal angioplasty and stenting is still indicated but we need: a better patient and lesion selection; improvements in techniques and maybe the use of protection devices to reduce the risk of RF deterioration after renal stenting.

Atorvastatin therapy is associated with improvement of oxidized low-density lipoprotein cholesterol levels, which correlates with the degree of stenosis in patients with carotid atheromatosis with and without prior angioplasty.

AIM: Oxidized low-density lipoprotein (oxLDL) is a pivotal factor of the atheromatous process. Statins reduce atheromatosis and cardiovascular risk. The aim of the present study was to investigate the effect of statin therapy on circulating oxLDL and the possible impact of such effect on stenosis due to carotid artery atheromatosis. METHODS: A total of 100 patients (76 males, median age 68 years) with carotid atheromatosis were enrolled. Those with stenosis >70% (n=50) were pre-treated with carotid angioplasty, whereas those with <70% were treated conservatively. Both groups were given low-dose atrorvastatin, tittered to maintain LDL cholesterol <100 mg/dL. Anthropometrics, complete lipid profile, and oxLDL were obtained in 1, 3, 6 and 12 months. Stenosis was evaluated by ultrasonography at baseline and 12 months. RESULTS: Lipid profile significantly improved at 12 months and oxLDL fell from 62.26+/-22.03 mg/dL at baseline to 44.49+/-21.75 mg/dL at 12 months (P<0.001). In the invasively pretreated group no restenosis was noticed; in the conservatively treated group a significant reduction of stenosis was demonstrated (47.6+/-13.2% vs 37.7+/-15.7%, P<0.001). The decrease of oxLDL correlated with the reduction of stenosis (r=0.17, P=0.018). In multivariate analysis, oxLDL was an independent risk factor for re-stenosis (hazard ratio=4.319, P<0.001). CONCLUSION: A marked reduction of oxLDL was shown in patients with carotid atheromatosis treated with low-dose atorvastatin. Moreover, oxLDL could be a measure of the degree of stenosis in such patients.

Carotid angioplasty in asymptomatic patients undergoing CABG surgery.

AIM: Although there are studies reporting that carotid endarterectomy (CEA) is recommended before or concomitant to coronary artery bypass grafting (CABG) in patients with severe carotid stenosis, controversies still exist. Carotid artery stenting (CAS) has been recently introduced as an alternative revascularization therapy in high-risk patients. The aim of this study was to demonstrate, whether CAS is safe as an alternative treatment to carotid CEA, in asymptomatic candidates for CABG surgery. METHODS: Forty-one patients with severe carotid and coronary artery disease were studied. The mean age was 65 years; 91% were males. Within 1 week of the CAS intervention all patients underwent CABG surgery. A brain protection device was used in all CAS interventions. Balloon PTA and stenting was performed in all subjects. Adjunctive therapy with heparin was used during the procedure and clopidogrel was started immediately after cardiac surgery. Patients were assessed neurologically before and after the procedure (immediately after the CAS, at 24h, at 30 days, at 3, 6 and 12 months). The primary end point was the incidence of TIA, stroke, or death at 30 days. RESULTS: Internal carotid artery lesions of > 80%, were reduced by CAS to < 20% in all cases, achieving a procedural success of 100%. There were no neurological complications, such as TIA and stroke, or death, up to 12 months follow up. One patient developed acute coronary syndrome the day after CAS and was treated accordingly. CONCLUSION: Our results show that CAS, with brain protection in asymptomatic patients undergoing CABG surgery is feasible and safe and could be a good alternative to CEA.

Reduction of capsule endoscopy reading times by unsupervised image mining.

The screening of the small intestine has become painless and easy with wireless capsule endoscopy (WCE) that is a revolutionary, relatively non-invasive imaging technique performed by a wireless swallowable endoscopic capsule transmitting thousands of video frames per examination. The average time required for the visual inspection of a full 8-h WCE video ranges from 45 to 120min, depending on the experience of the examiner. In this paper, we propose a novel approach to WCE reading time reduction by unsupervised mining of video frames. The proposed methodology is based on a data reduction algorithm which is applied according to a novel scheme for the extraction of representative video frames from a full length WCE video. It can be used either as a video summarization or as a video bookmarking tool, providing the comparative advantage of being general, unbounded by the finiteness of a training set. The number of frames extracted is controlled by a parameter that can be tuned automatically. Comprehensive experiments on real WCE videos indicate that a significant reduction in the reading times is feasible. In the case of the WCE videos used this reduction reached 85% without any loss of abnormalities.

Carotid angioplasty and stenting: how to avoid complications.

Carotid angioplasty and stenting (CAS) has been proposed as an alternative to surgery and is now more and more performed and well accepted, at least for high surgical risk patients. However complications and particularly embolic strokes, even with a meticulous technique, can occur at any step of the procedure. Silent embolism is detected after CAS and may be a problem that needs to be discussed. To avoid and reduce these complications associated with CAS we must have: good indications depending on good patients and lesions selection. New parameters have been proposed particularly for asymptomatic lesions, correct technique, embolic protection devices (EPD) are mandatory for any CAS. New techniques will be presented. The choice of the EPD depends on the clinical status of the patient, the lesion morphology and characteristics, the anatomy of the artery, good choice of the stent and correct implantation (all stents are not equivalent), pharmacological adjuncts, experienced operators, good team. With all these considerations CAS can now be performed with acceptable outcomes and in certain population the results are comparable or superior to surgery. The results of ongoing randomized trials are awaited.

Embolic protection for renal artery stenting.

UNLABELLED: A renal artery stenosis (RAS) is frequent and usually caused by atherosclerosis. Percutaneous renal artery angioplasty (PTRA) and stenting gives good immediate and long-term RESULTS: Concern has arisen in the postprocedural deterioration of the renal function (RF), which may occur in 20-40% of the patients therefore limiting the immediate benefits of the technique. Atheroembolism seems to play an important role in postprocedural deterioration. The authors postulated that the use of renal embolic protection devices could reduce the risk of renal embolism and avoid deterioration of the RF. One hundred forty-eight PTRA and stenting procedures were performed under protection in 121 hypertensive patients (M: 85), mean age: 64.5+/-11.8 years (22-87) with atherosclerotic renal artery stenosis. Eleven patients had solitary kidneys and 48 had renal insufficiency. Both occlusion balloons (N=46) and filters (N=95) were used. Of the 95 filters, the new FiberNet EP system (Lumen Biomedical) was included. This filter has the ability to capture particles as small as 30-40 microns without compromising flow. Generated debris was then removed and analysed, and blood pressure and serum creatinine levels were followed. Immediate technical success: was achieved in 100% os the cases. 112/141 lesions were stented directly. Visible debris with Percusurge (Medtronic) was aspirated and removed under aspiration from all patients and in 80% of the cases with filters. Debris was aspirated in 100% of the cases completed with the FiberNet). The mean particulate retrieved with the Percusurge system was 98.1+/-60.0 mu with a mean diameter ranging from 201+/-76 m (38-6 206). Mean occlusion time was 6.55+/-2.46 min and mean time in situ (filters) 4.2+/-1.1 min. Five times more particulate was removed with the FiberNet than with current available filters. One acute RF deterioration was observed. The mean follow-up was 29.6+/-14 months and the mean creatinine level remained constant during follow-up. At 6 months (101 patients) one deterioration of the RF in a patient with renal insufficiency at baseline was observed, 25 improvements in patients with renal insufficiency were noted, and 73 stabilizations. In conclusion 99% of the patients were stabilized or improved. After 2 years (84 patients) 95% of the patients remained stabilized (N=60) or showed improvements (N=20), and 4 patients had deterioration of RF (5%). The preliminary results suggest the feasibility and safety of distal protection during renal interventions to protect against atheroembolism and consequential deterioration of RF after the procedure. The beneficial effects of this technique should be evaluated further in randomized studies.

Carotid angioplasty and stenting in octogenarians: is it safe?

PURPOSE: Elderly patients have a higher risk of complications in carotid endarterectomy. The aim of the study was to evaluate whether carotid artery stenting (CAS) performed in octogenarians also increases the procedure related risk. METHODS: 870 patients (male 626) mean age 70.9 +/- 9.3 years underwent 930 CAS for de novo lesions (n = 851) restenoses (n = 54) post radiation (n = 14) inflammatory arteritis (n = 9) post trauma aneurysms (n = 2). Indications for treatment: symptomatic carotid stenosis > or = 70% (n = 577) or asymptomatic stenosis > or = 80%. Patients were separated into two age groups: <80 years (749 patients, 806 CAS) and >80 years (121 patients, 124 CAS). 187 CAS performed without protection (N.P-) 6 patients >80 years, 743 with protection (NP+) (occlusion balloon: 334, filters: 404, reversal flow: 6) 118 patients >80 years. Data analysis included neurological complications, death and myocardial infarction (MI) rate at 30 days, anatomical particularities. Technical points will be described depending on the age of the patient. RESULTS: Technical success 804/806 in patients <80 years, 123/124 in patients >80 years (NS). 30 days outcomes: in the patient group <80 years we observed 9 TIA (1.1%) 3 without NP (1.7%) 6 with NP (0.9%), 5 minor strokes (0.6%) 2 without NP (1.1%) 3 with NP (0.5%), 3 major strokes: 2 without NP (1.1%) 1 with NP (0.2%), 5 deaths (0.6%) 2 without NP (1.1%) 3 with NP (0.5%). Death/stroke/MI: 14 (1.8%) 6 without NP (3.3%), 8 with NP (1.3%). In the group >80 years, we observed 2 TIA (1.7%) 1 without NP 1 with NP (0.92%) 1 minor stroke without NP (17%) no major stroke, no death. Death/stroke/MI 1 without NP (17%). CONCLUSION: CAS can be performed in elderly patients without higher risk than in younger patients. But good indications, a meticulous technique, protection devices are mandatory and some technical points must be pointed out to avoid neurological complications and failures.

How to avoid complications associated with carotid angioplasty and stenting.

Carotid angioplasty and stenting (CAS) has been proposed as an alternative to surgery and is now performed more frequently and is well accepted, at least for high surgical risk patients. However, complications and particularly embolic strokes, even with a meticulous technique, can occur at any step of the procedure. Silent embolism is detected after CAS and may be a problem that needs to be discussed. To avoid and reduce these complications associated with CAS, it is important to have good indications dependent upon on good patient and lesions selection, as well as correct technique. New parameters have been proposed, particularly for asymptomatic lesions. The authors consider that embolic protection devices (EPDs) are mandatory for CAS, and new techniques will be presented. The choice of the EPD depends on the clinical status of the patient, the lesion morphology and characteristics, and the anatomy of the artery. All stents are not equivalent and so a good choice of the stent is necessary to avoid and reduce the complications associated with CAS, and experienced operators are also needed. With all these considerations, CAS can now be performed with acceptable outcomes and in certain population the results are comparable or superior to surgery. The results of ongoing randomized trials are awaited.

Percutaneous transluminal angioplasty of the subclavian arteries.

AIM: The aim of this study was to review the feasibility, safety and long-term results of subclavian artery (SA) angioplasty. METHODS: Over 14 years, 237 patients (males: 135; mean age: 64+/-12 years) underwent percutaneous treatment for SA occlusive disease. Indications for treatment were upper limb ischemia (n=125), vertebrobasilar insufficiency (n=128), coronary steal (n=11) and anticipated coronary bypass surgery in asymptomatic patients (n=26). A total of 192 arteries were stenosed and 45 occluded. Mean percentage stenosis was 81.9+/-7.6% and mean lesion length was 23.8+/-8.8 mm. Percutaneous techniques included retrograde femoral (n=163), brachial artery (n=47) access or both (n=14) and in 4 cases the ''pull through technique''. An isolated balloon angioplasty was performed in 59 cases. We implanted 132 balloon expandable stents and 32 self-expandable stents. RESULTS: Technical success was obtained in 223 lesions (94%). Only 31 occlusions were recanalized (69%). Four periprocedural events occurred (1.2%), 1 major (fatal) stroke, 1 transient ischemic attack and 2 arterial thromboses. At follow-up (mean follow-up: 65.8+/-33.5 months), we had 27 restenoses (12%). Thirteen occurred following angioplasty alone (18.8%) and 14 following angioplasty and stent implantation (8.4%). Primary (PI) and secondary (PII) patencies on an intention to treat basis at 10-year follow-up were 78.1% and 84.5%, respectively. In patients without initial stent placement, the rates were 67.5% and 75.5%, while in those with stents the rates rose to 89.7% and 96.9% (P<0.01). PI for all recanalized lesions were 84.6%, 79.1% without stent, 89.7% with stent (P<0.04) and PII 91.6%, 88.5%, 96.9%, respectively (P<0.02). CONCLUSION: Percutaneous transluminal angioplasty is currently the treatment of choice for SA lesions. It is a safe and effective procedure associated with low risks and good long-term results. Stents seem to limit the restenosis rate and improve long-term results.

Recent advances in renal artery stenting.

Renal artery stenosis (RAS) is frequent and increasingly recognized thanks to technical improvements in duplex ultrasound, magnetic resonance angiography, computed tomography (CT) scanning, systematic renal angiography during cardiac catheterisation, coronary procedures and particularly in hypertensive or multivascular diseased patients. Renal artery angioplasty and stenting is the first treatment to be proposed for patients suffering from RAS. This procedure is largely performed with very good technical results, good anatomical results, a low complication rate and a good long-term patency. The technique has proven to be beneficial for preserving RF and stabilizing or improving BP in a large number of patients. Nevertheless, deterioration in RF after the procedure in 20-30% of cases may limit the immediate benefits of this technique. Atheroembolism seems to play an important role. Renal angioplasty with protection devices seems a promising technique that might become the standard of care in the future. Even so, some problems remain: the cost of the technique; the best protection device needs to be determined; protection devices specifically designed for the renal arteries are needed; indications have to be specified. Larger, randomised studies are awaited to confirm the usefulness of the technique.

Carotid angioplasty and stenting under protection. State of the art.

A carotid stenosis is responsible for about 30% of strokes occurring. Carotid endarterectomy (CEA) is considered to be the gold standard treatment of a carotid stenosis. Carotid angioplasty and stenting (CAS) is emerging as a new alternative treatment for a carotid artery stenosis, but the risk of neurological complications and brain embolism remain the major drawback to this procedure. So as to reduce the risk, we need: good indications, good patient and lesion selection; correct techniques; brain protection devices (cerebral protection devices should be routinely used and are mandatory for any procedure. Three types of protection devices are available: filters are the most commonly used. Nevertheless, all protection devices have limitations and cannot prevent from embolic events. However neurological complications can be reduced by 60%. New protection devices will be discussed); good choice of the stent and correct implantation (all stents are not equivalent and have different geometrical effects); pharmacological adjuncts; good team. Indications are well accepted for high-risk patients and recent studies have shown that CAS has superior short-term outcomes than CEA in this group of patients. Indications for low-risk and asymptomatic patients are controversial. New selection criteria have to be discussed. But there are enough reported data to conclude that CAS is also not inferior to CEA in low-risk and asymptomatic patients. In our series of 844 procedures, without protection (n = 187) 30-day death and stroke rate was 3.7% and with protection (n = 657) 1% (1.3% for symptomatic patients, 0.9% for asymptomatic patients, 1.4% in high-risk patients, 0.4% in low-risk patients). CAS under protection is the standard of care and is maybe becoming the gold standard treatment of a carotid stenosis at least in some subgroups of patients.