Viktor Berczi

Differential Effects of Etomidate, Propofol, and Midazolam on Calcium and Potassium Channel Currents in Canine Myocardial Cells

Background Intravenous anesthetics etomidate, propofol, and midazolam produce negative inotropic effects of various degrees. The mechanism underlying these differences is largely unknown. Methods The effects of intravenous anesthetics on L-type Calcium sup 2+, transient outward and inward-rectifier Potassium sup + channel currents (ICa, IKto, and IK1) were compared in canine ventricular cells using the whole-cell voltage-clamp technique. ICa and IK were elicited by progressively depolarizing cells from -40 to +40 mV, and from -90 to +60 mV, respectively. The peak amplitude and time-dependent inactivation rate of ICa and IK were measured before, during, and after the administration of equimolar concentrations (5, 30, or 60 micro Meter) of etomidate, propofol, or midazolam. Results Exposure to etomidate, propofol, and midazolam produced a concentration-dependent inhibition of ICa. Midazolam was the most potent intravenous anesthetic; at 60 micro Meter, etomidate, propofol, and midazolam decreased peak ICa by 16 +/- 4% (mean +/- SEM), 33 +/- 5%, and 47 +/- 5%, respectively. Etomidate, propofol, and midazolam given in a 60-micro Meter concentration decreased IKto by 8 +/- 3%, 9 +/- 2%, and 23 +/- 3%, respectively. IK1 was decreased by 60 micro meter etomidate and midazolam by 20 +/- 6% and 14% +/- 5%, respectively. Propofol had no effect on IK1. Conclusions At equimolar concentrations, intravenous anesthetics decreased the peak ICa, IKto, and IK1 with various degrees of potency. Effects of anesthetics on ICa were significantly greater compared with their effects on Potassium sup + currents. These findings suggest that the negative inotropic actions of etomidate, propofol, and midazolam are related, at least in part, to decreased ICa. Some effects, such as IK inhibition, may partially antagonize effects of decreased ICa. Indeed, the final effect of these intravenous anesthetics on myocardium will be the sum of these and other sarcolemmal and intracellular effects.

Angioplasty of the innominate artery in 89 patients: Experience over 19 years

Purpose: To assess retrospectively the success of percutaneous transluminal angioplasty (PTA) in treating innominate artery stenoses and occlusions in a large series of patients with long-term follow-up results. Methods: In symptomatic (upper limb claudication, transient ischemic attack, vertebrobasilar insufficiency) patients with high-degree (>60%) stenosis, innominate artery PTA was performed. Long-term follow-up was undertaken by blood pressure measurements on both arms as well as subclavian, right common carotid and right vertebral duplex scan. Results: Between 1981 and 1999, the primary success rate of 89 innominate artery PTA (84 stenoses, 5 occlusions) was 96.4%. Complications included one left occipital lobe infarction (2%), two puncture-site thromboses (3%) and four transient ischemic attacks (6%). Two patients with restenosis were successfully treated with re-PTA. Cumulative primary patency was 98 ± 2% at 6 months, 93 ± 4% at 16–117 months; secondary patency was 100% at 6 months, 98 ± 2% at 12–117 months. Sixty-one percent of the patients became symptomless, 32% improved, 7% showed no improvement. Conclusion: Angioplasty of the innominate artery has been proven to be safe and effective on a large series of patients. For innominate artery stenosis and short occlusion, PTA should be the treatment of choice.

Placement of Hemobahn stent-grafts in femoropopliteal arteries: Early experience and midterm results in 18 patients

PURPOSE To determine the outcome of a new polytetrafluoroethylene (PTFE)-covered stent-graft in the treatment of occlusive lesions of the femoropopliteal arteries. MATERIALS AND METHODS Eighteen patients with intermittent claudication (Fontaine stages IIb-IV; Rutherford classes I/2-III/5) and occlusive lesions of the superficial femoral and/or popliteal artery were treated with use of a new PTFE-covered stent-graft (Hemobahn). Indication for stent-graft insertion was an unsatisfactory result after balloon dilation. RESULTS Successful stent-graft placement was achieved in 17 patients (94%). In one patient, additional insertion of a Palmaz stent was necessary because of a stent-graft wrinkle. Mean ankle-brachial index increased from 0.72 +/- 0.15 preoperatively to 0.94 +/- 0.17 postoperatively (P =.028). Fifteen patients (83%) experienced an initial improvement of at least one clinical stage. Primary patency was 61% +/- 11% at 3 months and 49% +/- 12% at 6 months. Stent-graft occlusion was observed in 13 patients (72%). In four patients, the stent-graft was reopened percutaneously by balloon angioplasty (n = 2) and/or rotational thrombectomy (n = 2). Therefore, the secondary patency rate was 67% +/- 11% at 3 months and 61% +/- 11% at 6 months. Patency rates proved to be significantly lower for stent-grafts longer than 10 cm (P =.03). Intimal hyperplasia at the proximal or distal end of the stent-graft was observed in seven patients (39%). Complications such as access site hematoma (n = 3), distal thromboembolism (n = 2), and abscess formation around the stent-graft (n = 1) were observed. CONCLUSION Despite excellent initial angiographic results, the patency rate in lesions treated with the Hemobahn stent-graft in this small study was unsatisfactory. Use of stent-grafts longer than 10 cm and the occurrence of intimal hyperplasia proved to be major factors in the reduction of long-term patency rates.

Long-term retrievability of IVC filters: should we abandon permanent devices?

Thromboembolic disease produces a considerable disease burden, with death from pulmonary embolism in the UK alone estimated at 30,000–40,000 per year. Whilst it is unproven whether filters actually improve longevity, the morbidity and mortality associated with thromboembolic disease in the presence of contraindications to anticoagulation is high. Thus complications associated with filter insertion, and whilst they remain in situ, must be balanced against the alternatives. Permanent filters remain in situ for the remainder of the patient’s life and any complications from the filters are of significant concern. Filters that are not permanent are therefore attractive in these circumstances. Retrievable filters, to avoid or decrease long-term filter complications, appear to be a significant advance in the prevention of pulmonary embolism. In this review, we discuss the safety and effectiveness of both permanent and retrievable filters as well as the retrievability of retrievable inferior vena cava (IVC) filters, to explore whether the use of permanent IVC filters can be abandoned in favor of retrievable filters. Currently four types of retrievable filters are available: the Recovery filter (Bard Peripheral Vascular, Tempe, AZ, USA), the Günther Tulip filter (Cook, Bloomington, IN, USA), the OptEase Filter (Cordis, Roden, The Netherlands), and the ALN filter (ALN Implants Chirurgicaux, Ghisonaccia, France). Efficacy and safety data for retrievable filters are as yet based on small series, with a total number of fewer than 1,000 insertions, and follow-up is mostly short term. Current long-term data are poor and insufficient to warrant the long-term implantation of these devices into humans. The case of fractured wire from a Recovery filter that migrated to the heart causing pericardial tamponade requiring open heart surgery is a reminder that any new endovascular device remaining in situ in the long term may produce unexpected problems. We should also bear in mind that the data on permanent filters are much more robust, with reports on over 9,500 cases with follow-up of up to 8 years. The original implantation time of 10–14 days has been extended to more than 100 days as the mean implantation time with some of the filter types. Follow-up (preferably prospective) is necessary for all retrievable filters, whether or not they are retrieved. Until these data become available we should restrict ourselves to the present indications of permanent and retrievable filters. If long-term follow-up data on larger numbers of cases confirm the initial data that retrievable filters are as safe and effective as permanent filters, the use of the retrievable filters is likely to expand.

Timing and frequency of complications after carotid artery stenting: what is the optimal period of observation?☆

OBJECTIVE Currently our standard of practice is that patients undergoing carotid artery stenting (CAS) may be safely discharged on the first day post-procedure. However, many patients are completely independent on the evening of procedure. Therefore we sought to establish the safety and feasibility of same-day discharge by assessing frequency and time of complications in the first 30 days after CAS. METHOD Case records for 208 consecutive patients who had undergone CAS from October 1999 to October 2002 were retrospectively reviewed. Excluded were four cases in which combined CAS and carotid endarterectomy was performed to treat synchronous stenosis. Of the remaining 204 cases, involving 201 patients (three patients underwent staged bilateral CAS), 173 (84.8%) were symptomatic and 31 (15.2%) were asymptomatic. RESULT Thirty-eight major events or death (inclusive of all neurologic events and any complications that required treatment) were recorded in the first 30 days after CAS, for an event rate of 18.6% per case. These were 7 (3.4%) major access site complications; 18 (8.8%) neurologic events, of which 10 (4.9%) were transient ischemic events and 8 (3.9%) were strokes (including minor, major, and fatal stroke); 8 (3.9%) cardiovascular complications; and five (2.5%) other events. Twenty (52.6%) events occurred in the first 6 hours after CAS, 2 (5.3%) between 6 and 12 hours, 3 (7.9%) between 12 and 24 hours, and 13 (34.2%) 24 hours to 30 days post procedure. Four (2.0%) deaths were recorded in this period, 1 secondary to stroke, 1 from a perforated myocardium from a temporary pacing wire, and 2 from unrelated causes. The 30-days stroke and death rate was 5.4% (11 of 204 patients). CONCLUSION Time of complications suggests that outpatient performance of CAS is feasible and safe in selected patients.

Percutaneous endovascular treatment of innominate artery lesions: A single-centre experience on 77 lesions

PURPOSE To assess primary success and safety of percutaneous transluminal angioplasty and/or stenting of innominate artery lesions and to compare its 30-day stroke/mortality level with the literature data. METHODS A total of 72 patients (77 stenoses, five recurrent, 58 symptomatic and 39 female) with seven innominate vessel occlusions, nine subocclusive lesions and 61 significant (>60%) stenoses of innominate artery treated between 2000 and 2009 were retrospectively reviewed. With the exception of seven, all procedures were performed using a transfemoral approach. A stent was implanted in 49 (63.6%) cases. Follow-up included neurological examination, carotid duplex scan and office/telephone interview. RESULTS Primary technical success was 93.5% (72/77). There was neither periprocedural (<48 h) death, nor major neurological complication. Minor periprocedural neurological complications consisted of 2/72 (2.6%) ipsilateral TIAs. Access site complications included 4 (5.2%) access site bleedings. Follow-up was achieved in 65/72 (90.3%) of all patients and 68 (88.3%) of all procedures for a mean of 42.3 months and revealed neither major neurological complication, nor additional TIA. The cumulative primary patency rate was 100% at 12 months, 98+/-1.6% at 24 months, and 69.9+/-8.5% at 96 months. The cumulative secondary patency rate was 100% at 12 and at 24 months, and 81.5+/-7.7% at 96 months. Log-rank test showed no significant difference (p=0.79) in primary cumulative patencies between PTA alone (n=28) or PTA/stent (n=49). CONCLUSION Transfemoral PTA with or without stent appears to be a safe treatment option for innominate artery lesions.

Heritability of central blood pressure and arterial stiffness: a twin study.

Objective: Central blood pressure and aortic stiffness have been consistently reported as strong cardiovascular risk factors. Twin studies by comparing identical with nonidentical twins produce information on the relative contribution of genes and environment. Methods: One hundred and fifty-four monozygotic (MZ) and 42 dizygotic (DZ) twin pairs (age 43 ± 17 years) from Hungary and the United States underwent brachial and central augmentation index (AIx), brachial and central pressure, and aortic pulse wave velocity (PWV) measurements with the invasively validated Arteriograph device. Bivariate Cholesky decomposition models were applied. Results: Age-adjusted, sex-adjusted and country-adjusted heritability was 60.0% for central SBP [95% confidence interval (CI), 44.8–69.6%], 50.1% for aortic PWV (95%CI, 26.0–66.8%), 48.7% for aortic AIx (95%CI, 1.7–74.0%), 46.8% for brachial AIx (95%CI, 1.1–73.8%), 46.7% for central pulse pressure (PP) (95%CI, 12.4–61.4%), and 30.0% for brachial PP (95%CI, 0.0–53.4%). Central SBP and PP had strong bivariate correlations with brachial (r = 0.461 and 0.425) and central AIx (r = 0.457 and 0.419), as well as with aortic PWV (r = 0.341 and 0.292, all P < 0.001). Brachial PP had a weak correlation with brachial AIx (r = −0.118, P < 0.05), central AIx (r = −0.122, P < 0.05), and none with aortic PWV (r = 0.08, P = n.s.). Genetic factors explained a moderate phenotypic correlation between central PP, SBP, brachial SBP and aortic PWV. Conclusions: Central systolic and PPs, brachial PP, AIx, aortic PWV are moderately heritable. A moderate genetic covariance among aortic PWV and central PP, central SBP and brachial SBP was found.

Early Experience and Midterm Follow-up Results with a New, Rotational Thrombectomy Catheter

AbstractPurpose: To assess the efficacy and safety of the Rotarex rotational thrombectomy catheter in treating occlusions of the femoropopliteal arteries. Methods: The Rotarex catheter (Straub Medical, Switzerland) is a rotational thrombectomy device which is supposed to be able to remove fresh and partially organized clot material from an acutely or subacutely occluded vessel. Nineteen limbs of 18 patients (10 women, 8 men; mean age 72.9 ± 7.3 years) with acute or subacute (23 ± 16 days) occlusions of the middle or distal third of the superficial femoral artery or the popliteal artery were treated. The occlusions were 3–20 cm long. Results: Thrombectomy was technically successful in 15 of 19 vessels (79%). The primary procedural success including additional procedures such as angioplasty and/or stent-graft placement in 17 limbs was 94%. The mean ankle-brachial index improved from 0.36 ± 0.26 (before thrombectomy) to 0.81 ± 0.21 (2 days after the procedure) (p = 0.012). Clinical symptoms shifted to at least one Fontaine stage lower in 13 limbs. As complications we observed two perforations (arteries showing heavily calcified plaques), one arteriovenous fistula and three distal embolizations. One perforation, the fistula and one intimal tear after percutaneous transluminal angioplasty were treated with covered stents; the three distal embolizations were treated successfully with aspiration or Rotarex thrombectomy. In the other perforation the intervention was terminated. None of the complications needed surgical treatment. The complication rate was 31.5%. Follow-up studies showed three early (4–11 days) and six late (1–6 months) reocclusions. The cumulative primary patency rate was 68 ± 12% at 3 months, and 39 ± 13% at 6, 12 and 19 months; the secondary patency rate was 68 ± 12% at 3 months and 53 ± 13% at 6, 12 and 20 months. Conclusion: The Rotarex thrombectomy catheter is effective and quick in treating acute and subacute occlusions of the superficial femoral and popliteal arteries. It should not be used in arteries with heavily calcified plaques because of the risk of perforation. Limited long-term patency is mainly due to the complexity of the underlying lesion. Our results suggest that the Rotarex mechanical thrombectomy catheter is effective and might serve as an alternative treatment modality to intra-arterial lysis.

Venous Myogenic Tone and Its Regulation Through K+ Channels Depends on Chronic Intravascular Pressure

In this study, we compared the level of myogenic tone and its negative-feedback control through specific K+ channels in two types of human veins (saphenous [SV] and cephalic [CV] veins), which experience different ranges of pressure in vivo. We also investigated whether an experimental model of increased venous pressure in rats exposed to head-up tilt for 2 weeks produced changes similar to those observed in the human veins. Cylindrical vein segments were cannulated, their diameters were measured, and the intraluminal pressure was set at different levels (2 to 30 mm Hg) in vitro. Acetylcholine test showed that during the regular harvesting process 76% of the human SVs exposed for coronary bypass grafts had no functional endothelium. We found significant myogenic tone in the human SV, where the in vivo pressure is high, but it was not present in the human CV, where the in vivo pressure is low. The nonspecific K+ channel antagonist, tetraethylammonium (TEA), decreased the diameter of the human SV but not the CV. Iberiotoxin and 4-aminopyridine, blockers of the Ca(2+)-sensitive (KCa) and voltage-gated K+ (KV) channels, also decreased the diameter of the human SV by 10.2 +/- 4.8% and 19.5 +/- 4.7%, respectively. In the rat SV, significant myogenic tone was found, but TEA had no effect, even after 2 weeks of in vivo pressure increase in the hindlimb by head-up tilt. We conclude that (1) an increased venous myogenic tone correlates with higher chronic intraluminal pressure loads, (2) KCa and KV channels counterregulate the myogenic tone in human, but not in rat, saphenous vein, (3) the counterregulatory effect is more effective at high than at low intraluminal in vitro pressure levels, and (4) its development is probably a long-term process.

Clear cell renal cell carcinoma and papillary renal cell carcinoma: differentiation of distinct histological types with multiphase CT.

PURPOSE Conventional clear cell renal cell carcinoma (ccRCC) and papillary renal cell carcinoma (pRCC) have different behavioral characteristics and clinical management strategies (nephrectomy vs. nephron-sparing surgery). Our aim was to retrospectively evaluate the contrast enhancement pattern of ccRCC and pRCC and evaluate its possible diagnostic role for preoperative differentiation using a standardized protocol. MATERIALS AND METHODS Quadriphasic multidetector computed tomography (CT) images (unenhanced, corticomedullary, nephrographic, and excretory phases) of 19 patients with 20 ccRCC and 14 patients with 15 pRCC lesions (mean ages, 62.3±14.1 and 61.4±13.7 years, respectively) were reviewed retrospectively. The attenuation characteristics were compared with the attenuation of the normal renal cortex using either multiple 10 mm2 regions of interest or whole tumor attenuation measurements. The degree of contrast enhancement was also compared. RESULTS Univariate analysis revealed that ccRCC lesions showed higher mean attenuation values on the corticomedullary and nephrographic phases compared with pRCC masses (P < 0.05) using both measurement techniques. CONCLUSION The findings underscore the importance of multiphase CT in the differentiation of these two subtypes of RCC using standard assessment techniques. The measurement of the degree of enhancement on contrast-enhanced multidetector CT may be a simple and useful method to radiologically differentiate between the two histological types of RCC.