Robotic assistance is increasingly used to improve patient outcomes and clinician occupational safety during percutaneous coronary and peripheral vascular interventions. We report the first use of the CorPath GRX Robotic System for assistance during balloon angioplasty and stenting for the treatment of severe bilateral renal artery stenosis.
Key words: renal artery stenosis, renovascular hypertension, medically refractory hypertension, robotics,
percutaneous peripheral vascular intervention
Renal artery stenosis caused by atherosclerotic disease, renal trauma, or thromboembolic occlusion produces renovascular hypertension with a subsequent rise in systemic arterial pressure.1 Downstream sequelae may include progressive, medically refractory systemic hypertension, increasing restriction of renal blood flow, impaired volume control, circulatory congestion, and irreversible kidney injury.
While the efficacy of various treatment options for renal artery stenosis have been a matter of debate,1–3 balloon angioplasty with stent placement is one approach that may improve systemic symptoms in carefully selected patients.1,2,4,5 More than 30 years ago, percutaneous approaches to intervention revolutionized the speed and outcomes of coronary and, subsequently, peripheral revascularization.6 However, procedural complications remained and the requirement for fluoroscopy presented its own set of occupational hazards to clinicians, including radiation exposure and orthopedic injury from heavy protective clothing. In recent years, robotic systems such as the CorPath System (Corindus, Inc), have been introduced to further improve the speed and accuracy of percutaneous vascular intervention while also reducing clinicians’ occupational exposure to the radiation associated with fluoroscopy.6–8
The second-generation CorPath GRX Robotic System is currently cleared for use in the United States for percutaneous coronary and peripheral vascular interventions, but to date, there are few peer-reviewed reports of its use for peripheral interventions. Here, we report our first experience using the CorPath GRX robot to assist with balloon angioplasty and placement of renal artery stents to treat severe bilateral renal artery stenosis in a patient with refractory hypertension.
In August 2018, a 46-year-old man presented with refractory hypertension (203/93 mm Hg on admission) despite being on multiple antihypertensive medications including metoprolol, nifedipine, and hydrochlorothiazide with preserved renal function. His history was significant for tobacco abuse and recurrent admissions for chest pain, and his body mass index was 21 kg/m2. Angiography identified severe bilateral renal artery stenosis, with a proximal 95% focal stenosis of the ostial left renal artery (Figure 1A) and proximal 80% focal stenosis of the right renal artery (Figure 2A). Following a discussion of treatment options and risks, the patient consented to bilateral stenting of the renal arteries in the setting of refractory hypertension with multiple admissions and bilateral renal artery stenosis.
The patient was prepped and draped in sterile fashion, and local anesthetic (lidocaine) was injected into the right groin for arterial access. Following patient sedation (midazolam and hydralazine), an 8 French introducer sheath with .038-inch guidewire (Ultimum) was introduced manually into the right common femoral artery, and an 8 French guide catheter (Mach 1, Boston Scientific) was inserted over the wire. Heparin was administered (8000 units, IV bolus), followed by fentanyl (50 mcg). Angiography was performed to confirm the atherosclerotic obstruction of bilateral renal arteries.
After positioning the tableside arm of the CorPath GRX robotic system, the Y-connector component of the system was connected to the proximal end of the guide catheter, and then loaded into the appropriate drive track within the single-use cassette of the robotic drive unit. An .018-inch × 150 cm guidewire (V-18 ControlWire, Boston Scientific) was introduced through the Y-connector into the guide catheter. Once the proximal end of the guidewire was loaded into the guidewire track of the cassette, the interventionalist was seated at the shielded workstation and used robotic manipulation to carry out the remainder of the wiring and stenting procedures.
The guidewire was advanced up the femoral artery to the aorta, and through the ostium of the left renal artery to the proximal segment. Pre-dilation was achieved by loading a rapid-exchange 6.0 mm × 20 mm × 135 cm balloon catheter (Sterling Monorail, Boston Scientific) into the robot, advancing it to the obstruction, and inflating it at 4.0 atm. A rapid-exchange 5.0 mm × 19 mm × 150 cm pre-mounted, bare-metal stent system (Express SD, Boston Scientific) was loaded and deployed (Figure 1B). Intravascular ultrasound (IVUS) imaging of the stented segment was performed to confirm adequate size of the vessel for optimization. Post dilation with the Sterling 6.0 mm x 20 mm balloon resulted in mild underexpansion of the stent, so a 7.0 mm × 20 mm balloon (Advance 18LP, Cook Medical) was used to achieve complete expansion. Final angiogram of the left renal artery confirmed adequate stent expansion and apposition with brisk flow (Figure 1C). Repeat IVUS imaging confirmed adequate stent expansion and apposition (Figure 1D). The procedure was repeated for the right renal artery (Figure 2B-D) with robotic-assisted wiring, pre-dilation, stenting, intravascular imaging, and post dilation. Final angiogram of the right renal artery confirmed adequate stent expansion and apposition with brisk flow.
Total fluoroscopy time was 15.1 min, with a fluoroscopy dose of 171 mGy. Contrast volume was 80 cc iopamidol (IsoVue, Bracco Diagnostics).
Following removal of all devices and guides, hemostasis of the right common femoral artery access site was achieved using an Angio-Seal VIP closure device (Terumo Interventional Systems). There were no intraprocedural complications, insertion-site bleeding, or hematoma. The patient recovered completely and was given instructions to continue dual antiplatelet therapy with aspirin and clopidogrel, and to continue to pursue aggressive optimization of hypertension. The patient was seen in follow-up 1 month later with significant improvement in blood pressure at 150/87 mm Hg on the same medications.
Conflicting results from observational and randomized, controlled clinical trials has resulted in ongoing controversy regarding the clinical utility or benefit of renal artery revascularization.1–3 While the ASTRAL and CORAL trials failed to find long-term advantages in survival, renoprotection, or reduced requirements for antihypertensive therapy, these trials were notably limited by their tendency toward selection bias for lower-risk patients.2 However, experts in the field contend that a significant subset of higher-risk patients may yet stand to benefit from revascularization.1,2,4,5 In particular, patients with medically refractory hypertension, early renal insufficiency, significant (>75%) and progressive stenosis, and bilateral lesions may benefit.
To our knowledge, this is the first report of robotic-assisted stent placement within the renal vascular system. The robotic system used in this report has been available for cardiovascular indications for much longer than for peripheral vascular interventions, and thus the majority of the available literature features cardiovascular results.
In 2016, Mahmud and colleagues reported the results of RAPID, a prospective single-arm trial of the CorPath GRX robot in the treatment of 20 patients with symptomatic (Rutherford class 2 to 5) peripheral artery disease of the femoropopliteal artery.9 Technical, safety, and clinical success were achieved for all 29 lesions treated, with no periprocedural, device-related serious adverse events. The authors noted that fluoroscopy times were comparable to those associated with manual interventions, but that in the robotic-assisted cases, the interventionalist was spared a significant amount of radiation exposure, as well as the need for heavy leaded clothing, because control of the robot occurs behind a shielded workstation. This finding was consistent with our experience. The case was completed easily with the robotic arm, with no need for the operator to be exposed to intraprocedural radiation and, furthermore, no need to wear a heavy, leaded apron. Meanwhile, the use of contrast medium was noted to be low in this case.
In 2016, Behnamfar and colleagues published the first use of the CorPath robotic system for lower-extremity revascularization in a 56-year-old man with peripheral artery disease and activity-limiting claudication.10 This case was a technical and clinical success, and the authors noted that use of the robotic system could potentially improve accuracy of stent measurement and placement. Accuracy remains an important benefit of the robotic system because it facilitates precise delivery of the balloon and stent in a vascular bed that could be negatively affected by embolization triggered as a result of large catheter/device manipulation.
We found that the robotic system was a useful tool for facilitating balloon angioplasty and accurate placement in stenotic renal arteries, with the added benefit of reduced radiation exposure for the interventionalist.
Jeanne McAdara, PhD, provided professional assistance with manuscript preparation, which was funded by Corindus, Inc.
Disclosure: The authors report no financial relationships or conflicts of interest regarding the content herein. Corindus, Inc. provided funds for professional medical writing. The medical writer worked under the direction of the author. It should be noted that the CorPath GRX System is not universally compatible with all available guidewires and catheters, and thus the user should consult the operator’s manual for compatible device information prior to conducting any case with the system.
Manuscript submitted February 10, 2019; accepted February 15, 2019.
Address for correspondence: Jon C. George, MD, FACC, FSCAI, FAHA; Director, Cardiac Cath Lab; Einstein Medical Center; 5501 Old York Road, Philadelphia, PA 19130; Office Phone: (215) 456-7245; Office Fax: (215) 456-3533. Email: firstname.lastname@example.org
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