Endovascular Therapies for Vascular Disease

Changes in Coronary Flow Reserve following Stent Implantation in the Swine Descending Thoracic Aorta

Purpose:

To evaluate coronary flow reserve (CFR) changes following stent implantation in the descending thoracic aorta (DTA) of a porcine model.

Methods:

Six pigs (3 males; 40 to 44 kg) were anesthetized and kept on mechanical ventilation. A 6-F guiding right Judkins catheter was advanced under fluoroscopy to the right coronary artery, and a pressure wire with a temperature sensor was placed within the vessel lumen at a distance of 4 cm from the ostium. CFR was estimated by the thermodilution method before and after maximal coronary vasodilation with 20 mg of intracoronary papaverine. Aortography was also performed to measure aortic diameter. Subsequently, a self-expanding vascular stent was deployed into the DTA just below the left subclavian artery (LSA), and CFR was measured again. All animals were maintained for 3 weeks; at the end of this period, a further CFR was calculated using the same procedure.

Results:

The mean aortic diameter below the LSA was 12.15±0.15 mm. Following stent deployment, the mean aortic diameter measured at the stented segment was 12.58±0.11 (p=0.001 versus baseline). The mean CFR value was 4.7062.00 before stent implantation, 2.6860.86 immediately after, and 4.0561.15 at 3 weeks after stenting. Accordingly, CFR values were significantly depressed immediately after stent placement compared with baseline (p=0.027). However, CFR values obtained 3 weeks following stent deployment were similar to the initial values (p=0.59).

Conclusion:

Stent deployment in the normal swine DTA produces a significant immediate decrease in CFR, which is attenuated 3 weeks later. The clinical impact of CFR changes following DTA endografting remain to be elucidated.

When ballooning alone is enough: successful treatment of hypertension secondary to renal artery fibromuscular dysplasia using angioplasty

A case of hypertension secondary to renal artery fibromuscular dysplasia (FMD), successfully treated by balloon angioplasty is presented to highlight that for this specific condition balloon angioplasty remains the treatment of choice.

Virtual Reality Simulation Training can Improve Inexperienced Surgeons' Endovascular Skills

PURPOSE

The aim of this study was to evaluate virtual reality (VR) simulation for endovascular training of surgeons inexperienced in this technique.

METHODS

Twenty consultant vascular surgeons were divided into those who had performed >50 endovascular procedures (e.g. aortic and carotid stent) as primary operator (n=8), and those having performed <10 procedures (n=12). To test for endovascular skill rather than procedural knowledge, all subjects performed a renal artery balloon angioplasty and stent procedure. The simulator uses real tools with active force feedback, and provides a realistic image of the virtual patient. Surgeons with endovascular skills performed two repetitions and those without completed six repetitions of the same task. The simulator recorded time taken for the procedure, the amount of contrast fluid used and total fluoroscopy time.

RESULTS

Initially, surgeons with endovascular skills were significantly faster (median 571.5 vs. 900.0 s, p=0.039) and used less contrast fluid (19.1 vs. 42.9 ml, p=0.047) than inexperienced operators, though differences for fluoroscopy time were not significant (273 vs. 441 s, p=0.305). Over the six sessions, the inexperienced group made significant improvements in performance for time taken (p=0.007) and contrast fluid usage (p=0.021), achieving similar scores at the end of the training program to the experienced group.

CONCLUSIONS

Surgeons with minimal endovascular experience can improve their time taken and contrast usage during short-phase training on a VR endovascular task. VR simulation may be useful for the early part of the learning curve for surgeons who wish to expand their endovascular interests.