nitinol and Hypertension

Hypertension remains a major public health burden despite the plethora of therapeutic agents available for this disorder, compelling innovation of alternate therapies including interventional approaches where necessary. The kidney is a major player in the pathophysiology of this disease with increased sympathetic activity being the key factor in the initiation and maintenance of drug resistant hypertension in many patients. Thus renal denervation targeted at decreasing sympathetic drive is becoming the apparent choice in carefully selected patients with resistant hypertension who have exhausted all medical options. The Symplicity and EnligHTN trials using first and second generation catheters respectively have demonstrated that renal sympathetic denervation results in significant blood pressure reduction. The initial renal denervation catheter used in the Symplicity trial was a single electrode system. Refinement of this process has led to the EnligHTN catheter's design. This is a multielectrode self-expanding nitinol basket that allows the positioning of the thermal injury pattern to be pre-specified and in theory lead to better positioning of the lesions. We present a review of the premise behind renal artery denervation, discuss the data and early technologies focusing on the characteristics and utility of the first multielectrode renal denervation device, the EnligHTN renal denervation catheter.

Topics: Alloys; Catheter Ablation; Electrodes; Humans; Hypertension; Kidney; Patient Selection; Renal Artery; Sympathectomy

Coral reef aorta (CRA) is a rare condition, characterised by rock-hard calcification of the juxta-renal and supra-renal aorta with luminal encroachment causing significant stenosis of the aorta and its branches. It usually presents as resistant hypertension, renal dysfunction, mesenteric ischaemia, limb claudication or embolic manifestations. Although surgical thrombo-endarterectomy along with bypass graft to the affected visceral arteries remains the cornerstone of treatment, it is associated with considerable mortality and morbidity, especially in patients with pre-existing comorbidities. Here we report an elderly female of resistant hypertension, who had successful endovascular aortic stenting using a non-graft self-expanding stent. Her blood pressure dramatically improved following endovascular management. In comparison to the conventional surgical approach, endovascular stenting can be an alternative, less invasive approach in selected CRA patients.

Topics: Aged; Alloys; Aortic Diseases; Computed Tomography Angiography; Diabetic Angiopathies; Female; Humans; Hypertension; Stents; Tomography, X-Ray Computed; Treatment Outcome; Vascular Calcification

To investigate the possible role of stent selection and procedure-related vessel diameter changes in the development of persisting hemodynamic depression (PHD) and to demonstrate the effectiveness and safety of permanent pacemaker implantation in patients with refractory PHD.. Data from 584 procedures performed in 542 patients (398 men; mean age 67.3 years) between 2008 and 2011 using Wallstent, Precise, and Xact stents in a nonrandomized fashion were analyzed retrospectively. Cardiovascular risk factors and lesion, stent, and balloon characteristics were collected, and the pre- and postprocedure diameters of the common carotid artery (CCA) and internal carotid artery were measured. PHD was defined as any episode of hypotension (systolic blood pressure <90 mm Hg) and/or bradycardia (heart rate <60/min) lasting >6 hours. Risk factors for PHD were sought using logistic regression analyses; the results are presented as the odds ratio (OR) and 95% confidence interval (CI).. The incidence of PHD was 37.0% (216/584). Refractory PHD was encountered in 9 patients; among these, 6 were successfully treated with pacemaker implantation. A history of prior ipsilateral carotid endarterectomy (OR 0.44, 95% CI 0.22 to 0.87, p=0.019) and the presence of a contralateral high-grade stenosis (OR 0.12, 95% CI 0.02 to 0.95, p=0.045) were independent protective factors, while calcification (OR 1.5, 95% CI 1.03 to 2.18, p=0.034), involvement of the carotid bulb (OR 2.56, 95% 1.62 to 4.03, p<0.001), and implantation of a nitinol stent (adjusted OR 1.62, 95% CI 1.12 to 2.34, p=0.011) were independent risk factors for developing PHD after carotid artery stenting. The ratio of the post-/preprocedure CCA diameter (p=0.002), the stent to CCA diameter ratio (p=0.009), and the presence of residual stenosis (p=0.009) were significantly higher in the PHD group.. Stent selection and procedure-related changes in vessel diameter may have an influence on the development of PHD. Permanent pacemaker implantation is an effective treatment option in patients with refractory PHD.

Topics: Aged; Alloys; Angioplasty, Balloon; Body Mass Index; Bradycardia; Carotid Artery, Common; Carotid Artery, Internal; Carotid Stenosis; Female; Hemodynamics; Humans; Hypertension; Incidence; Male; Middle Aged; Platelet Aggregation Inhibitors; Postoperative Care; Preoperative Care; Retrospective Studies; Risk Assessment; Risk Factors; Stents; Treatment Outcome

Topics: Alloys; Angiography; Angioplasty, Balloon; Arteriovenous Shunt, Surgical; Embolization, Therapeutic; Humans; Hypertension; Kidney Transplantation; Ligation; Male; Middle Aged; Renal Dialysis; Stents; Treatment Failure; Uremia

Percutaneous transluminal renal angioplasty and stent placement with use of a coronary protection device was performed in a total of four patients with hypertension (n = 4) and/or renal insufficiency (n = 3) referred for revascularization of five renal arteries. Renal revascularization was successful in all five renal arteries (100%), but renal revascularization under protection by the FilterWire EX was achieved in only three of five renal arteries (60%). In one of these three, only a suboptimal seal was achieved between the vessel wall and the filter basket. Nevertheless, use of the device was safe and fibrin and/or cholesterol fragments were retrieved from three renal arteries. The FilterWire EX needs to be modified for the renal circulation to achieve the full theoretical advantages of these systems in this vascular bed.

Topics: Aged; Aged, 80 and over; Alloys; Angioplasty, Balloon; Cholesterol; Embolism; Female; Fibrin; Filtration; Humans; Hypertension; Male; Middle Aged; Polyurethanes; Renal Artery Obstruction; Renal Insufficiency; Retrospective Studies; Stents; Treatment Outcome