Cryoplasty for peripheral arterial disease

Endothelinergic Contractile Hyperreactivity in Rat Contralateral Carotid to Balloon Injury: Integrated Role for ETB Receptors and Superoxide Anion

Temporal consequences of neurocompensation to balloon injury on endothelinergic functionality in rat contralateral carotid were evaluated. Rats underwent balloon injury in left carotid and were treated with CP-96345 (NK₁ antagonist). Concentration-response curves for endothelin-1 were obtained in contralateral (right) carotid at 2, 8, 16, 30, or 45 days after surgery in the absence or presence of BQ-123 (ET_A antagonist), BQ-788 (ET_B antagonist), or Tempol (superoxide-dismutase mimic). Endothelin-1-induced calcium mobilization was evaluated in functional assays carried out with BQ-123, BQ-788, or Tempol. Endothelin-1-induced NADPH oxidase-driven superoxide generation was measured by lucigenin chemiluminescence assays performed with BQ-123 or BQ-788. Endothelin-1-induced contraction was increased in contralateral carotid from the sixteenth day after surgery. This response was restored in CP-96345-treated rats. Endothelium removal or BQ-123 did not change endothelin-1-induced contraction in contralateral carotid. This response was restored by BQ-788 or Tempol. Contralateral carotid exhibited an increased endothelin-1-induced calcium mobilization, which was restored by BQ-788 or Tempol. Contralateral carotid exhibited an increased endothelin-1-induced lucigenin chemiluminescence, which was restored by BQ-788. We conclude that the NK₁-mediated neurocompensatory response to balloon injury elicits a contractile hyperreactivity to endothelin-1 in rat contralateral carotid by enhancing the muscular ET_B-mediated NADPH oxidase-driven generation of superoxide, which activates calcium channels.

Drug-Eluting Stent vs Percutaneous Transluminal Angioplasty for Treatment of Femoropopliteal In-Stent Restenosis: Results From a Retrospective 1-Year Multicenter Study

PURPOSE

To compare drug-eluting stent (DES) implantation with percutaneous transluminal angioplasty (PTA) in the treatment of femoropopliteal in-stent restenosis (ISR).

METHODS

A comparison was performed of data from 112 ZEPHYR registry patients (mean age 74±9 years; 60 men) with 119 femoropopliteal ISR lesions treated with a drug-eluting stent (Zilver PTX) with historical data from 116 patients (mean age 72±8 years; 83 men) with 133 lesions treated with PTA. The patients were stratified for analysis by lesions with (101/252, 40%) and without (n=151) in-stent occlusion. The primary outcome measure was the 1-year incidence of recurrent restenosis; the secondary outcome was major adverse limb events (MALE). Multivariate logistic regression analysis was performed to look for any independent association of DES implantation with 1-year recurrent restenosis in the respective subgroups; results are presented as the odds ratio (OR) and 95% confidence interval (CI).

RESULTS

In the subgroup without in-stent occlusion, there was no significant difference between DES and PTA in the 1-year incidence of recurrent restenosis (40.5% vs 45.7%, p=0.583, respectively) or MALE (27.8% vs 20.7%, p=0.322, respectively). However, in the subgroup with in-stent occlusion, DES implantation was associated with significantly lower incidences of recurrent restenosis (44.1% vs 90.3% for PTA, p<0.001) and MALE (25.5% vs 53.6% for PTA, p<0.001). Multivariate analysis confirmed that DES implantation had a significant independent negative association with the risk of recurrent restenosis in the subgroup with occlusion (OR 0.2, 95% CI 0.1 to 0.6, p=0.006).

CONCLUSION

DES implantation may be more effective than PTA in the management of femoropopliteal ISR with occlusion, but equally effective to PTA in nonocclusive ISR lesions. These results require confirmation in prospective randomized studies.

Hemodynamic and neural responses to renal denervation of the nerve to the clipped kidney by cryoablation in two-kidney, one-clip hypertensive rats

Renal artery stenosis is increasing in prevalence. Angioplasty plus stenting has not proven to be better than medical management. There has been a reluctance to use available denervation methodologies in this condition. We studied conscious, chronically instrumented, two-kidney, one-clip (2K-1C) Goldblatt rats, a model of renovascular hypertension, to test the hypothesis that renal denervation by cryoablation (cryo-DNX) of the renal nerve to the clipped kidney decreases mean arterial pressure (MAP), plasma and tissue ANG II, and contralateral renal sympathetic nerve activity (RSNA). Five-week-old male Sprague-Dawley rats underwent sham (ShC) or right renal artery clipping (2K-1C), placement of telemetry transmitters, and pair-feeding with a 0.4% NaCl diet. After 6 wk, rats were randomly assigned to cryo-DNX or sham cryotreatment (sham DNX) of the renal nerve to the clipped kidney. MAP was elevated in 2K-1C and decreased significantly in both ShC cryo-DNX and 2K-1C cryo-DNX. Tissue norepinephrine was ∼85% lower in cryo-DNX kidneys. Plasma ANG II was higher in 2K-1C sham DNX but not in 2K-1C cryo-DNX vs ShC. Renal tissue ANG II in the clipped kidney decreased after cryo-DNX. Baseline integrated RSNA of the unclipped kidney was threefold higher in 2K-1C versus ShC and decreased in 2K-1C cryo-DNX to values similar to ShC. Maximum reflex response of RSNA to baroreceptor unloading in 2K-1C was lower after cryo-DNX. Thus, denervation by cryoablation of the renal nerve to the clipped kidney decreases not only MAP but also plasma and renal tissue ANG II levels and RSNA to the contralateral kidney in conscious, freely moving 2K-1C rats.