Elias Kehagias

Graft inflow stenosis induced by the inflatable ring fixation mechanism of the Ovation stent-graft system: hemodynamic and clinical implications.

Purpose: To investigate the observed inflow stenosis at the O-rings of the Ovation stent-graft and evaluate its hemodynamic and clinical impact. Methods: The study involved 49 consecutive patients (48 men; mean age 71.2±7.7 years) treated successfully with the Ovation abdominal aortic stent-graft between June 2011 and January 2014 at a single center. Cross-sectional area and radius measurements of the infrarenal aorta just proximal to the sealing mechanism, as well at the site of stenosis, were measured from 3D reconstructions of the 1-month postoperative computed tomographic angiograms. Based on Poiseuilles law, the predicted pressure drop was calculated for each patient based on the length of the stenosis. Invasive blood pressure measurements at 3 levels (proximal to the inflatable rings, halfway inside the stenosis, and distal to the stenosis) were obtained in 10 patients intraoperatively. Ankle-brachial index (ABI) values preoperatively were compared to those after the procedure for all patients to assess the clinical impact of this phenomenon. Results: Median internal cross-sectional area at the site of the stenosis was significantly reduced compared to the area just proximal to the O-rings [57% reduction: 123 mm2 (range 28–254) vs. 283 mm2 (range 177–531), respectively; p<0.001]. The same was observed for the radius [6.5 mm (range 3–9) vs. 9.5 mm (range 7.5–13), respectively; p<0.001]. Based on the median 15 mm length of the stenosis (range 13–17) observed in the study population, a median pressure drop of 0.13 mmHg (range 0–0.25) along the stenosis was calculated. Invasive blood pressure measurements indicated a non-significant pressure change along the stenosis (e.g., 0.7 mmHg between the proximal level and halfway inside the stenosis). ABI remained practically unchanged postoperatively. Conclusion: The advantages of the Ovation devices unique sealing mechanism come at the expense of a median area inflow stenosis of ∼60%. This stenosis does not cause a hemodynamically significant pressure drop. Future modification of the graft ring design may be needed in order to reduce this stenosis.

Current role of microwave ablation in the treatment of small hepatocellular carcinomas

Percutaneous radiofrequency ablation (RFA) can be as effective as surgical resection in terms of overall survival and recurrence-free survival rates in patients with small hepatocellular carcinoma (HCC). Effectiveness of RFA is adversely influenced by heat-sink effect. Other ablative therapies could be considered for larger tumors or for tumors located near the vessels. In this regard, recent improvements in microwave energy delivery systems seem to open interesting perspectives to percutaneous ablation, which could become the ablation technique of choice in the near future. Microwave ablation (MWA) has the advantages of possessing a higher thermal efficiency. It has high efficacy in coagulating blood vessels and is a relatively fast procedure. The time required for ablation is short and the shape of necrosis is elliptical with the older systems and spherical with the new one. There is no heat-sink effect and it can be used to ablate tumors adjacent to major vessels. These factors yield a large ablation volume, and result in good local control and fewer complications. This review highlights the most relevant updates on MWA in the treatment of small (<3 cm) HCC. Furthermore, we discuss the possibility of MWA as the first ablative choice, at least in selected cases.

Totally Percutaneous Endovascular Aneurysm Repair Using the Preclosing Technique: Towards the Least Invasive Therapeutic Alternative.

Endovascular aneurysm repair (EVAR) offers a minimally invasive approach for the treatment of abdominal aortic aneurysms, whereas arterial closure devices have made totally percutaneous EVAR feasible. This is a retrospective analysis of patients undergoing EVAR in a single institution, between May 2011 and October 2014 using surgical or percutaneous access. Hemostasis after percutaneous access was achieved with 2 Perclose ProGlide suture-mediated devices and a preclosing technique. Technical success, local complications, procedural times, length of hospitalization, and need for analgesics are recorded and compared between groups. Among 82 patients/164 groins, 120/164 (73%) groins underwent percutaneous and 44/146 (27%) surgical access. An average 2.2 devices per access site was used. Technical success was 95% (114/120). Local complications (3.3% vs. 11.4%, P=0.05), procedural times (90 vs. 112 min, P=0.05), hospitalization (2 vs. 5 d, P<0.001), and postoperative analgesics (0.7 vs. 4.4 g IV paracetamol, P=0.01) were significantly reduced after percutaneous access which overall seems safe and effective to perform EVAR.

Bifurcated Aortoiliac Endograft Limb Occlusion during Deployment and Its Bailout Conversion Using the External Iliac Artery to Internal Iliac Artery Endograft Technique

Endovascular aneurysm repair has become the preferred method to treat abdominal aortic aneurysms (AAAs). The Ovation TriVascular Stent-Graft system introduces a unique concept of separation of the metal (stent) and fabric (graft) portion of the endografts main body to facilitate delivery through ultra-low profile 14F devices. In the setting of a narrow distal aneurysmal lumen, usually due to the presence of thrombus, deployment of this endograft may be complicated by folding and collapse of the (unsupported by a stent) aortic body or limbs, making catheterization and ballooning impossible. We present a case of Ovation endograft contralateral limb collapse in a tight AAA lumen due to thrombus deposition, which led to folding and total occlusion of the limb and made limb catheterization impossible. This is a real-life example of how the external iliac artery to internal iliac artery endograft technique may be used as a bailout procedure, converting the procedure into an aortouni-iliac graft. To our knowledge, this is the first reported bailout use of this technique in English literature which may be used in selected cases.

Vibrational angioplasty in recanalization of chronic femoropopliteal arterial occlusions: single center experience.

PURPOSE This prospective study aims to present the overall success rate, safety and long-term outcome of vibrational angioplasty technique, in the treatment of chronic total femoropopliteal occlusions in our institute. METHODS Between October 2000 and December 2008, patients with chronic total femoropoliteal arterial occlusions, treated with vibrational angioplasty during the same session after a failed attempt with conventional recanalization technique, were included. Patients follow up included serial ankle-brachial index measurements and arterial duplex ultrasound examinations at 1, 3, 6, 12, 24, 36 and 48 months. RESULTS Twenty-seven patients (16 males and 11 females) and twenty-eight lesions were included in our study. Twenty-five lesions (89.3%) were successfully recanalized. Pain relief was noticed in twenty-one cases. From ten lesions with tissue loss (ulcer or gangrene) in successfully recanalized occlusions, six healed without major, or minor amputation. One non-healing amputation stump was healed after recanalization, without further complications. Four limbs underwent amputation (one minor and three major) despite successful recanalization, however all had an excellent healing of the amputation stump without further complications. The Kaplan-Meier test demonstrated 90%, 85% and 70% amputation-free survival rate at 12, 24 and 36 months, respectively. No major or minor complications were encountered. CONCLUSIONS Vibrational angioplasty is a safe, effective and durable endovascular technique for the treatment of chronic total occlusions in patients with limb ischemia that would be difficult to recanalize using conventional intraluminal techniques.

The “L-shaped tunneling technique”: a modified technique facilitating a more discreet implantable port positioning

Purpose Venous port catheters, also known as “totally implantable venous access devices” (TIVADs), are now the standard of care in patients requiring long-term intermittent intravenous drug administration. We describe a modification of the implantation technique that we use in our department in order to improve the cosmetic result of a TIVAD. Methods After ultrasound-guided venous access in the internal jugular vein (IJV) or another appropriate vein has been obtained, we create a port pocket in the deltopectoral groove, in the upper-lateral chest wall, in a “far-lateral-oblique” orientation, respecting the individual patients relaxed skin tension lines. Then we create a subcutaneous tunnel using a straight metal tunneler in two steps: first tunneling cranially and perpendicular to the port incision for a small distance, and then, after turning the tunneler at a right angle continuing in a straight line until we exit at the venous access site. Results This configuration not only prevents catheter kinking, to ensure uninhibited flow, but also allows us to place the port pocket in a more discreet position, in order to offer a better cosmetic result to our patients. Conclusions Adoption of a “far-lateral-oblique” port implantation site along with the “L-shaped tunneling technique” will offer doctors who are implanting TIVADs a useful alternative for a better cosmetic result.

Common and uncommon complications of totally implantable central venous ports: A pictorial essay

Purpose The purpose of this study is to present the characteristic radiologic features of common and uncommon complications in totally implantable central venous ports. Material and Methods The authors reviewed 138 implantations of central venous ports in oncologic patients during an 18-month period and present the characteristic imaging features of the complications detected. Results All chest ports were placed via the internal jugular vein using both fluoroscopic and ultrasound guidance. The technical success rate was 99.3% (137/138). All catheter or port-related complications were retrospectively assessed. Sixteen complications were detected during the follow-up period, and catheter removal was required in 10 patients. Conclusions Image-guided central venous port catheter implantation is a very safe procedure with a low rate of complications. The typical imaging features of common and uncommon complications are very helpful in establishing the correct diagnosis and thus tailoring the appropriate therapy.

Acute TIPS occlusion due to iatrogenic arteriovenous shunt in a cirrhotic patient with total portal vein thrombosis.

A 69-year-old man with portal hypertension was admitted with decompensated alcoholic cirrhosis and diuretic resistant ascites. Ultrasound revealed partial portal thrombosis. Due to diuretic intolerance, transjugular intrahepatic portosystemic shunt (TIPS) was decided during which a hepatic arterial branch was inadvertently catheterized. Finally, TIPS was created, but the patient continued gaining weight. Color-Doppler ultrasonography (CDUS) showed upper stent part patency with absence of flow in lower stent portion. Twenty-five days later, the patient presented melena. Endoscopy revealed blood emerging from the Vater papilla. Hepatic angiography revealed arteriovenous shunt between a hepatic arterial branch and the proximal part of the TIPS shunt. Covered stent placement restored sufficient TIPS flow. The patient deteriorated and died 1 month later. We found out that our major technical drawback was that we did not inject a small amount of contrast after puncturing the supposed portal vein, in order to confirm correct position of the needle.

Transcatheter arterial chemoembolization combined with radiofrequency or microwave ablation for hepatocellular carcinoma: a review

Hepatocellular carcinoma (HCC) is the sixth most common type of malignancy. Several therapies are available for HCC and are determined by stage of presentation, patient clinical status and liver function. Local–regional treatment options, including transcatheter arterial chemoembolization, radiofrequency ablation or microwave ablation, are safe and effective for HCC but are accompanied by limitations. The synergistic effects of combined transcatheter arterial chemoembolization and radiofrequency ablation/microwave ablation may overcome these limitations and improve the therapeutic outcome. The purpose of this article is to review the current literature on these combined therapies and examine their efficacy, safety and influence on the overall and recurrence-free survival in patients with HCC.

Proper technique of port puncture in the deltopectoral groove: the “port pinning technique”

to tell you a story: a few years ago, a nurse of our hospital complained to a surgeon who was using the inverted “V” shape method for ports, that his ports had increased resistance in flushing. “All ports have the same resistance in flushing” the surgeon replied with absolute certainty. “All of YOUR ports have the same resistance in flushing, but all the rest are much easier to flush” said the nurse. It turned out that the surgeon, although absolutely certain on port’s normal resistance in flushing, had never tried to flush a port placed by anyone else but himself. In our department, we use the “L-shaped tunneling” method to implant our patients’ ports in the deltopectoral groove for a more discreet appearance, and make use of the “port pinning technique” during puncture for safe port access.