Patients, operators, and evaluation forms
A total of nine patients underwent embolisation using the Hourglass device. They were four females and five males (average age 52 years; age range 25–84 years). Five patients underwent renal artery embolisation, three had left gonadal vein embolisation for varicoceles and a single patient underwent embolisation of the gasttroduodenal artery (GDA) for a bleeding duodenal ulcer after failed endoscopic treatment.
The procedures were performed by two different primary operators with 22 years and 9 years of interventional radiology experience, respectively. A post-procedure evaluation form was filled out after each procedure by the primary operator. The primary operator was asked to grade satisfaction with the device in relation to the following attributes: usability of the delivery system; device deployment; device visibility under fluoroscopy; and ease of repositioning, if attempted. Each was graded on a three-point scale (easy, somewhat difficult or unsatisfactory). The stability and trackability were also scored on a three-point scale (good, fair or poor).
Device
The Hourglass device comprises an hourglass-shaped Nitinol frame, the proximal half of which is covered with PTFE (Fig. 1). Unconstrained, the device measures 20 mm in length and 10 mm in diameter, although the final device length depends on vessel size. It is designed as a ‘one size fits all’ device for use in vessels with diameters in the range of 3–8 mm. The distal end of the device acts as an anchor, while the covered proximal end provides immediate occlusion of the vessel when deployed. The hourglass configuration aims to harness the effect of blood pressure to augment the compressive forces on the frame providing additional anchoring and occlusion.
The device is delivered over a 0.018” guidewire in a similar manner to an endovascular stent. The delivery system consists of an inner body, an outer body and a rotating haemostatic valve (RHV) with a side port. There are radiopaque markers on either end of the device, on the distal tip of the outer body and on the proximal tip and mid portion of the inner body.
Deployment technique
The device was deployed in an identical manner in all cases (Fig. 2). A 0.018” wire was positioned within the target vessel across the desired location for deployment. The delivery system was then introduced and the distal tip placed just beyond the desired landing site. The inner body and embolic device were then advanced within the outer body until the distal end of the embolic device was aligned with the distal end of the outer body. The RHV on the inner body was then loosened and the device partially deployed by holding the inner body stationary and withdrawing the outer body in a “pinch-pull” manner (Fig. 2b). At this point, the device may be re-sheathed by re-advancing the outer body provided the outer body tip marker does not pass the proximal marker of the inner body (Fig. 2c).
Once the device was anchored distally, full deployment was achieved by pulling the outer body back to unsheath the proximal end of the device (Fig. 2d). Pushing slightly forward on the inner sheath disengaged the device allowing the inner body and outer body to be simultaneously withdrawn, while keeping the guide wire stationary (Fig. 2). Finally, the wire was withdrawn through the device. Contrast injection via the outer body side port immediately confirmed the position of the device and assessed the adequacy of vascular occlusion.
Case illustrations
Renal artery embolisation
The procedure was carried out in five patients (A–E) via a right common femoral artery approach using a 6-Fr Destination sheath (Terumo Europe, Leuven, Belgium) placed in the proximal renal artery and a V-18 guidewire (Boston Scientific, Marlborough, MA, USA). Patients A and B had renal cell carcinomas which required de-vascularisation before surgical resection. Patient C underwent embolisation of a renal mass without subsequent surgery. Patient D developed a perinephric haemorrhage around a non-functioning left kidney on a background of prior transplant and anticoagulant medication. Patient E had a non-functioning left kidney with severe hydronephrosis. In all five patients, distal target organ embolisation was first performed using embospheres (Merit Medical Systems, South Jordan, UT, USA) before deployment of the plug. Patient A required additional coil embolisation of an upper pole branch arising proximally from the left renal artery (Fig. 3) and patient D required coil embolisation of the right adrenal artery.
Varicocele embolisation
All three patients (F–H) had symptomatic left sided varicoceles and underwent embolisation of the left gonadal vein. A right common femoral vein approach was used and a C2 catheter (Cook Medical, Bloomington, IN, USA) used to catheterise the left renal vein. The gonadal vein was selected using a hydrophilic guide wire and the C2 catheter advanced into the proximal portion. This was then exchanged for a 6-Fr sheath, which was advanced into the proximal left gonadal vein. Retrograde venography confirmed a dilated and incompetent left gonadal vein in all three cases. The vein was embolised with coils distally and the Hourglass device was deployed proximally (Fig. 4).
Gastroduodenal artery embolisation
One patient (I) presented with an upper gastrointestinal haemorrhage arising from a duodenal ulcer, confirmed with direct visualisation. Endoscopic attempts to control the haemorrhage were unsuccessful. The patient subsequently underwent GDA embolisation, using coils for the ‘back door’ supply from the superior mesenteric artery and the Hourglass device in the proximal GDA.