Radiofrequency Ablation of Solid Benign Thyroid Nodules.

Symptomatic solid benign thyroid nodules may present either as nonfunctioning nodules causing compressive symptoms or as hyperfunctioning nodules causing symptoms of hyperthyroidism. While surgical resection or radioiodine ablation of these nodules can be performed, percutaneous radiofrequency ablation (RFA) of benign solid thyroid nodules has been shown to be a safe and effective alternative in select patients. Preprocedural evaluation should include a history focusing on signs and symptoms of thyroid dysfunction, a physical exam, thyroid ultrasound, thyroid function tests, and discussion of key intraprocedural details with the patient such as the anesthesia plan and risks. Thyroid RFA can be safely performed as an outpatient procedure with less than 2% major and minor complication rates. This report will focus on the basic technique of performing RFA for symptomatic thyroid nodules.

Lead aVR predicts early revascularization but not long-term events in patients referred for stress electrocardiography.

BACKGROUND: Exercise stress electrocardiography (ExECG) is recommended as a first-line tool to assess ischemia, but standard ST-analysis has limited diagnostic accuracy. ST elevation in lead aVR has been associated with left main and LAD disease in the population undergoing coronary angiography but has not been studied in the general population undergoing stress testing for the initial evaluation of CAD without coronary angiography. We sought to determine the predictive value of lead aVR elevation for ischemia, early revascularization, and subsequent cardiac events in consecutive patients undergoing ExECG. METHODS AND RESULTS: The study cohort included 641 subjects referred for ExECG who were dichotomized by presence or absence of aVR elevation ≥1mm and compared for prevalence and predictors of ischemia and a composite of cardiac death, nonfatal myocardial infarction, and late revascularization. The cohort had a median age of 57 and 57% were male. The prevalence of aVR elevation was 11.5%. The prevalence of significant ischemia on patients who received imaging was significantly higher with aVR elevation (14.3% vs 2.3%, p<0.001). Early revascularization occurred in 10.9% with vs 0.2% without aVR elevation, p<0.001. No subjects without aVR elevation or ST-depression underwent early revascularization. However, cardiac event rates were similar over a median 4.0 years of follow-up with and without aVR elevation (2.8% vs. 2.6%, p = 0.80). aVR elevation did not predict long-term cardiac events by Kaplan-Meier survival analysis (p = 0.94) or Cox proportional hazards modeling (p = 0.35). CONCLUSIONS: aVR elevation during ExECG predicts ischemia on imaging and early revascularization but not long-term outcomes and could serve as a useful adjunct to standard ST-analysis and potentially reduce the need for concurrent imaging.

Suprarenal Inferior Vena Cava Filter Placement and Retrieval: Safety Analysis.

PURPOSE: To evaluate safety and retrieval success of retrievable suprarenal inferior vena cava (IVC) filters. MATERIALS AND METHODS: A retrospective chart review of patients who received a retrievable suprarenal IVC filter between January 2008 and December 2017 was conducted. Suprarenal IVC filters were placed in 24 female and 27 male patients. The most common indications for filter placement were IVC thrombus (n = 20; 39.2%) and iliofemoral venous thrombosis with contraindication to anticoagulation (n = 16; 31.3%). The most common indications for suprarenal placement were IVC thrombus (n = 20; 39.2%), anatomic variants (n = 17; 33.3%), and external IVC compression (n = 8; 15.8%). Duplicated IVC was the most common anatomic variant requiring suprarenal placement (n = 7; 13.7%). RESULTS: Günther Tulip (n = 40; 78.4%), Denali (n = 10; 19.6%), and Celect (n = 1; 2.0%) filters were used. Retrieval was attempted in 27 of the 51 filters placed (52.9%). Of the 27 attempted retrievals, the technical success rate was 100% (27/27). The median dwell time was 87.0 days (95% confidence interval, 28-137 d). One complication involving fractured struts during filter retrieval occurred. No significant change in craniocaudal filter position, lateral filter tilt, or renal function between placement and retrieval was observed (P < .05). There were no instances of indwelling filter fracture. CONCLUSIONS: Suprarenal IVC filters, when indicated, can be placed and retrieved with a low complication rate.

Outcomes of Hypertensive Patients with Renal Fibromuscular Dysplasia Compared with Patients with Concomitant Atherosclerotic Renal Artery Stenosis following Endovascular Therapy.

PURPOSE: To examine if the outcomes after endovascular treatment in hypertensive patients with renal artery fibromuscular dysplasia (FMD) and incidental atherosclerotic renal artery stenosis (ARAS) differ from the outcomes in patients with FMD alone. MATERIALS AND METHODS: All cases of patients with renal artery FMD undergoing percutaneous transluminal angioplasty during the period 2002-2012 were reviewed. The patients with complete data before and after the procedure were identified (N = 84). Based on the procedural reports, these patients were separated into two cohorts: patients with isolated FMD (n = 59) and patients with concomitant atherosclerotic renal artery stenosis and FMD (ARAS-FMD) (n = 25). The medical record of each patient was reviewed for baseline blood pressure, antihypertensive medication use, and renal function data and the same data after the procedure. Procedural details including the angiographic findings, the number of stents placed, the average number of revascularization procedures, and the number of patients requiring more than one revascularization procedure were noted. RESULTS: The study population included 68 patients (FMD, n = 46; ARAS-FMD, n = 22). Patients in the FMD and ARAS-FMD cohorts experienced comparable significant decreases in systolic and mean arterial pressures after endovascular intervention. There was no change in the number of antihypertensive medications after the procedure within or between groups. Patients in the ARAS-FMD cohort had lower baseline estimated glomerular filtration rates (P = .007); however, renal function stabilized in both groups after endovascular therapy. CONCLUSIONS: Patients with ARAS-FMD respond to endovascular therapy with outcomes similar to patients with isolated renal artery FMD.

Is fibromuscular dysplasia underdiagnosed? A comparison of the prevalence of FMD seen in CORAL trial participants versus a single institution population of renal donor candidates.

Renal artery fibromuscular dysplasia (FMD) may be underdiagnosed. We evaluated the prevalence of FMD in CORAL (Cardiovascular Outcomes in Renal Atherosclerotic Lesions) renal artery stent trial participants, in which FMD was an exclusion criterion for inclusion. We also evaluated the prevalence of FMD in a relatively healthy population of patients undergoing computed tomographic angiographic (CTA) screening for renal donor evaluation. All renal donor CTAs performed at our institution from January 2003 through November 2011 were retrospectively reviewed for the presence of FMD along with patient sex and age. These results were compared to angiographic core lab (ACL) findings for the CORAL trial. The CORAL ACL database contained 997 patients (mean age 69.3 years; 50% female). Fifty-eight (5.8%) CORAL trial patients (mean age 71.8 years; 75.9% female) demonstrated incidental FMD. The renal donor cohort included 220 patients (mean age 40.5 years; 64.5% female). Five (2.3%) demonstrated FMD (mean age 48.6 years; all female). The odds of FMD in the CORAL cohort were 2.65 times that seen in the renal donor cohort (95% CI: 1.12, 7.57). In C: onclusion, the 5.8% prevalence of renal artery FMD in the CORAL trial population, the presence of which was biased against, suggests underdiagnosis.

Synthesis and biological evaluation of a fluorescent analog of phenytoin as a potential inhibitor of neuropathic pain and imaging agent.

Here we report on a novel fluorescent analog of phenytoin as a potential inhibitor of neuropathic pain with potential use as an imaging agent. Compound 2 incorporated a heptyl side chain and dansyl moiety onto the parent compound phenytoin and produced greater displacement of BTX from sodium channels and greater functional blockade with greatly reduced toxicity. Compound 2 reduced mechano-allodynia in a rat model of neuropathic pain and was visualized ex vivo in sensory neuron axons with two-photon microscopy. These results suggest a promising strategy for developing novel sodium channel inhibitors with imaging capabilities.

Synthesis and evaluation of hermitamides A and B as human voltage-gated sodium channel blockers.

Hermitamides A and B are lipopeptides isolated from a Papau New Guinea collection of the marine cyanobacterium Lyngbya majuscula. We hypothesized that the hermitamides are ligands for the human voltage-gated sodium channel (hNa(V)) based on their structural similarity to the jamaicamides. Herein, we describe the nonracemic total synthesis of hermitamides A and B and their epimers. We report the ability of the hermitamides to displace [(3)H]-BTX at 10 µM more potently than phenytoin, a clinically used sodium channel blocker. We also present a potential binding mode for (S)-hermitamide B in the BTX-binding site and electrophysiology showing that these compounds are potent blockers of the hNav1.2 voltage-gated sodium channel.

Temporal lobe epilepsy induces intrinsic alterations in Na channel gating in layer II medial entorhinal cortex neurons.

Temporal lobe epilepsy (TLE) is the most common form of adult epilepsy involving the limbic structures of the temporal lobe. Layer II neurons of the entorhinal cortex (EC) form the major excitatory input into the hippocampus via the perforant path and consist of non-stellate and stellate neurons. These neurons are spared and hyper-excitable in TLE. The basis for the hyper-excitability is likely multifactorial and may include alterations in intrinsic properties. In a rat model of TLE, medial EC (mEC) non-stellate and stellate neurons had significantly higher action potential (AP) firing frequencies than in control. The increase remained in the presence of synaptic blockers, suggesting intrinsic mechanisms. Since sodium (Na) channels play a critical role in AP generation and conduction we sought to determine if Na channel gating parameters and expression levels were altered in TLE. Na channel currents recorded from isolated mEC TLE neurons revealed increased Na channel conductances, depolarizing shifts in inactivation parameters and larger persistent (I(NaP)) and resurgent (I(NaR)) Na currents. Immunofluorescence experiments revealed increased staining of Na(v)1.6 within the axon initial segment and Na(v)1.2 within the cell bodies of mEC TLE neurons. These studies provide support for additional intrinsic alterations within mEC layer II neurons in TLE and implicate alterations in Na channel activity and expression, in part, for establishing the profound increase in intrinsic membrane excitability of mEC layer II neurons in TLE. These intrinsic changes, together with changes in the synaptic network, could support seizure activity in TLE.

2,4(5)-diarylimidazoles as inhibitors of hNaV1.2 sodium channels: pharmacological evaluation and structure-property relationships.

Sodium (Na) channels continue to represent an important target for the development of novel anticonvulsants. We have synthesized and evaluated a series of 2,4(5)-diarylimidazoles for inhibition of the human neuronal Na(V)1.2 Na channel isoform. Starting with the unsubstituted lead compound previously published 3, SAR studies were performed introducing substituents with different physico-chemical properties. Lipophilicity (log D(7.4)) and basicity (pK(a)) of the compounds were measured and submitted for QSPR investigations. Some of the active compounds described had IC(50) values that were considerably lower than our lead compound. In particular, the m-CF(3) disubstituted 22 was the most active compound, inhibiting hNa(V)1.2 currents within the nanomolar concentration range (IC(50)=200 nM). In comparison, lamotrigine and phenytoin, two clinically used anticonvulsant drugs known to inhibit Na channels, had IC(50)'s values that were greater than 100 microM.

2,4(5)-Diarylimidazoles: synthesis and biological evaluation of a new class of sodium channel blockers against hNa(v)1.2.

A small family of novel 2,4(5)-diarylimidazoles were prepared through a simple and efficient synthesis and evaluated as potential inhibitors of hNa(v)1.2 sodium channel currents. One member of this series (4) exhibited profound inhibition of Na(v)1.2 currents, emerging as a promising lead compound for further structure-activity relationship studies for the development of novel sodium channel blockers.