"Real World" Eligibility for Sacubitril/Valsartan in Unselected Heart Failure Patients: Data from the Swedish Heart Failure Registry.

PURPOSE: PARADIGM-HF demonstrated the superiority of sacubitril/valsartan over enalapril in patients with heart failure and reduced ejection fraction (HF-REF). How widely applicable sacubitril/valsartan treatment is in unselected patients with HF-REF is not known. We examined eligibility of patients with HF-REF for treatment with sacubitril/valsartan, according to the criteria used in PARADIGM-HF, in the Swedish Heart Failure Registry (SwedeHF). METHODS: Patients were considered potentially eligible if they were not hospitalized, had symptoms (NYHA class II-IV) and a reduced LVEF (≤ 40%), and were prescribed an angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB) at a dose equivalent to enalapril ≥ 10 mg daily. In these patients, we evaluated further eligibility according to the main additional PARADIGM-HF inclusion criteria. RESULTS: Of 12,866 outpatients in NYHA functional class II-IV with an LVEF ≤ 40%, 9577 were prescribed at least 10 mg of enalapril (or equivalent) daily. Complete additional data were available for 3099 of these patients (32.4%) and of them 75.5% were potentially eligible for treatment with sacubitril/valsartan. The most common reason for ineligibility was a low natriuretic peptide level (n = 462, 14.9%). Only a small proportion of patients were ineligible due to low eGFR or serum potassium level. Because only 78% of patients were taking ≥ 10 mg enalapril or equivalent daily, only 58.9% of all patients (75.5% of 78%) were eligible for sacubitril/valsartan. CONCLUSIONS: Between 34 and 76% of symptomatic patients with HF-REF in a 'real world' population are eligible for treatment with sacubitril/valsartan, depending on background ACEI/ARB dose. The most common reason for ineligibility is a low natriuretic peptide level.

A Preliminary Case Report of a High-Quality Cost-effective Rigid Laryngoscopy Setup.

OBJECTIVE: To evaluate a cost-effective modified rigid laryngoscopy setup with a portable light source and high-resolution commercially available digital camera for use in smaller otolaryngology and family practice clinics. METHODS: The modified setup was used to obtain images of the larynx using both a traditional light source and a portable light source. Varying shutter speeds and ISOs were evaluated, and the optimal settings were determined for the modified setup. RESULTS: Picture quality was adequate, and the portable light source was bright enough. ISO from 640 to 1600 with shutter speeds ranging from 1/60 to 1/160 are ideal under the normal light source, while it is better to set the ISO between 4000 and 10 000 with shutter speeds from 1/60 to 1/100 under the portable light source. Picture quality was adequate with a resolution of 2768 pixels × 1848 pixels with 350 dpi × 350 dpi. CONCLUSIONS: Results show that the modified setup obtains images of adequate quality for use in the clinic. Additionally, since the larynx requires the most illumination for endoscopic imaging, a similar setup would work for imaging the ear and nose. This setup may make laryngoscopic exams more accessible to patients at smaller laryngoscopy clinics or family practice providers.

Interferon γ is a STAT1-dependent direct inducer of BCL6 expression in imatinib-treated chronic myeloid leukemia cells.

B-cell CLL/lymphoma 6 (BCL6) exerts oncogenic effects in several human hematopoietic malignancies including chronic myeloid leukemia (CML), where BCL6 expression was shown to be essential for CML stem cell survival and self-renewal during imatinib mesylate (IM) treatment. As several lines of evidence suggest that interferon γ (IFNγ) production in CML patients might have a central role in the response to tyrosine kinase inhibitor (TKI) therapy, we analyzed if IFNγ modulates BCL6 expression in CML cells. Although separate IFNγ or IM treatment only slightly upregulated BCL6 expression, combined treatment induced remarkable BCL6 upregulation in CML lines and primary human CD34+ CML stem cells. We proved that during combined treatment, inhibition of constitutive signal transducer and activator of transcription (STAT) 5 activation by IM allowed the specific enhancement of the STAT1 dependent, direct upregulation of BCL6 by IFNγ in CML cells. By using colony-forming assay, we found that IFNγ enhanced the ex vivo colony or cluster-forming capacity of human CML stem cells in the absence or presence of IM, respectively. Furthermore, inhibition of the transcriptional repressor function of BCL6 in the presence of IM and IFNγ almost completely blocked the cluster formation of human CML stem cells. On the other hand, by using small interfering RNA knockdown of BCL6, we demonstrated that in an IM-treated CML line the antiapoptotic effect of IFNγ was independent of BCL6 upregulation. We found that IFNγ also upregulated several antiapoptotic members of the BCL2 and BIRC gene families in CML cells, including the long isoform of MCL1, which proved to be essential for the antiapoptotic effect of IFNγ in an IM-treated CML line. Our results suggest that combination of TKIs with BCL6 and MCL1 inhibitors may potentially lead to the complete eradication of CML stem cells.

Pulse pressure is not an independent predictor of outcome in type 2 diabetes patients with chronic kidney disease and anemia--the Trial to Reduce Cardiovascular Events with Aranesp Therapy (TREAT).

Pulse pressure (PP) remains an elusive cardiovascular risk factor with inconsistent findings. We clarified the prognostic value in patients with type 2 diabetes, chronic kidney disease (CKD) and anemia in the Trial to Reduce cardiovascular Events with Aranesp (darbepoetin alfa) Therapy. In 4038 type 2 diabetes patients, darbepoetin alfa treatment did not affect the primary outcome. Risk related to PP at randomization was evaluated in a multivariable model including age, gender, kidney function, cardiovascular disease (CVD) and other conventional risk factors. End points were myocardial infarction (MI), stroke, end stage renal disease (ESRD) and the composite of cardiovascular death, MI or hospitalization for myocardial ischemia, heart failure or stroke (CVD composite). Median (interquartile range) age, gender, eGFR and PP was 68 (60-75) years, 57.3% women, 33 (27-42) ml min(-1) per 1.73 m2 and 60 (50-74) mm Hg. During 29.1 months (median) follow-up, the number of events for composite CVD, MI, stroke and ESRD was 1010, 253, 154 and 668. In unadjusted analyses, higher quartiles of PP were associated with higher rates per 100 years of follow-up of all end points (P⩽0.04), except stroke (P=0.52). Adjusted hazard ratios (95% confidence interval) per one quartile increase in PP were 1.06 (0.99-1.26) for MI, 0.96 (0.83-1.11) for stroke, 1.01 (0.94-1.09) for ESRD and 1.01 (0.96-1.07) for CVD composite. Results were similar in continuous analyses of PP (per 10 mm Hg). In patients with type 2 diabetes, CKD and anemia, PP did not independently predict cardiovascular events or ESRD. This may reflect confounding by aggressive antihypertensive treatment, or PP may be too rough a risk marker in these high-risk patients.

Neonatal Repair in a Patient With Heterotaxy, Truncus Arteriosus, Pulmonary Artery Sling, and Tracheal Stenosis.

We present a newborn with heterotaxy features, multiple congenital anomalies, truncus arteriosus with long segment tracheal stenosis, and a left pulmonary artery sling. The patient had complete neonatal repair with slide tracheoplasty and repair of the left pulmonary artery sling with anterior translocation of the pulmonary artery. The truncus was repaired with a transventricular ventricular septal defect closure with a patch and right ventricle to pulmonary artery conduit. Complete repair of complex cardiac neonatal lesions with critical tracheal stenosis is feasible and should be the strategy of choice in these complex patients.

Current use of intralesional cidofovir for recurrent respiratory papillomatosis.

OBJECTIVES/HYPOTHESIS: The authors sought to define the indications, administration, and adverse events associated with intralesional cidofovir use for recurrent respiratory papillomatosis (RRP). STUDY DESIGN: Cross-sectional study. METHODS: A 21-question online survey was distributed to 115 selected adult and pediatric laryngeal surgeons internationally. Results were used to draft statements of best practice, which were approved by the full membership of the RRP Task Force. RESULTS: Eighty-two surgeons, who altogether presently manage 3,043 patients with RRP, responded to the survey. Seventy-four surgeons previously used cidofovir, reporting 1,248 patients in the last decade (estimated 801 adults and 447 children). Single indications for adjuvant cidofovir included six or more surgeries per year, increasing frequency of surgery, and extralaryngeal spread (in children). Most adult surgeons use 20 to 40 mg in <4 mL; pediatric surgeons use <20 mg in <2 mL. Scheduled administration following an initiation trial of five injections is common; cidofovir is discontinued following a complete response. Most surgeons biopsy routinely, use special informed consent, and are willing to participate in multi-institutional clinical trials on cidofovir uses, efficacy, and safety. CONCLUSIONS: Eighteen statements were approved by the RRP Task Force after discussion of the survey results. Intralesional cidofovir may be initiated if surgical debulking is required every 2 to 3 months. The concept of an adjuvant regimen with regular biopsy is favored. Administration should remain below established safe limits of dosing (3 mg/kg) and volume. Informed consent, including discussion of off-label use and acute kidney injury in children, is important. A special consent form sample is included. There remains a need for high-quality data.

The association between neutrophil gelatinase-associated lipocalin and clinical outcome in chronic heart failure: results from CORONA*.

OBJECTIVE: To study the prognostic value of neutrophil gelatinase-associated lipocalin (NGAL) in chronic heart failure (HF) of ischaemic aetiology. BACKGROUND: Neutrophil gelatinase-associated lipocalin is a marker of kidney injury as well as matrix degradation and inflammation and has previously been shown to be increased in HF. We investigated whether serum NGAL levels could provide prognostic information in chronic HF. METHODS: We assessed NGAL as a predictor of primary outcomes (cardiovascular death, nonfatal stroke and nonfatal myocardial infarction, n = 307) and all-cause mortality (n = 321), cardiovascular mortality (n = 259) and hospitalization (n = 647) as well as the number of hospitalizations during follow-up for all (n = 1934) and CV causes (n = 1204) in 1415 patients with chronic HF (≥60 years, New York Heart Association class II-IV, ischaemic systolic HF) in the CORONA population, randomly assigned to 10 mg rosuvastatin or placebo. Results. Multivariate analysis revealed that NGAL added significant information when adjusting for clinical variables, but was no longer significant when further adjusting for apolipoprotein A-1 (ApoA-1), glomerular filtration rate (GFR), C-reactive protein (CRP) and N-terminal pro-brain natriuretic peptide (NT-proBNP). However, belonging to the highest NGAL tertile was associated with more frequent hospitalization, even after adjusting for clinical variables, GFR and ApoA-1, but not after adjusting for CRP and NT-proBNP. There was no interaction between rosuvastatin treatment and NGAL. Conclusion. Neutrophil gelatinase-associated lipocalin added no significant information to NT-proBNP and GFR in a multivariate model for primary and secondary end-points.

Endoscopic changes in the upper airway after mandibular distraction osteogenesis.

INTRODUCTION: Children with micrognathia secondary to craniofacial disorders can experience significant airway and feeding difficulties. Mandibular distraction osteogenesis (MDO) is one treatment of severe micrognathia. We examined endoscopic images for upper airway (UA) soft tissue changes after MDO. We hypothesized that MDO produces consistent changes in UA soft tissue, which correlate with symptom resolution. MATERIALS AND METHODS: This retrospective chart review included 16 patients undergoing MDO from 2002 to 2007. Demographic data, symptom information, and preoperative and early and late postoperative endoscopic images were collected. Blinded randomized images of UA soft tissues were quantitatively analyzed using ImageJ. To compare nonstandardized images, ratios of UA dimensions were made. Preoperative and early and late postoperative ratios were statistically analyzed with Student's t-test. RESULTS: Sixteen patients with a mean age of 237 days were included. Mean distance distracted was 12 mm. There were significant changes in relative dimensions of the supraglottic space in the early postoperative period, which were not maintained in the late postoperative period. Nevertheless, all experienced complete relief of airway obstruction. DISCUSSION: Our study showed a significant increase in supraglottic space dimensions after MDO that was not maintained over time. This is likely because of the limitation of images and measurement methods. Despite this, significant clinical improvement was seen in all patients, with resolution of airway obstruction. This suggests supraglottic changes as well as tongue base alterations are related to clinical improvement. Further investigation of alterations in UA after MDO is needed to continue characterizing these changes.

Implementation of a program for surgical education in laryngology.

OBJECTIVES: To describe the implementation of a program for surgical education in laryngology. METHODS: Items necessary to modify a temporal bone lab for laryngeal dissection purposes were identified, and costs to do so were calculated. The prices and availability of human and canine laryngeal specimens to be used for teaching purposes were then compared. Endoscopic and open laryngeal surgery were performed on canine larynges to determine suitability as a teaching model. A laryngeal dissection course with teaching objectives was created and instituted in an Otolaryngology-Head and Neck Surgery residency training program. RESULTS: Modifications to convert an existing temporal bone lab into a laryngeal dissection lab cost $7,425. Canine larynges were found to strongly resemble human larynges and were easily used in a teaching model. They were more easily acquired and less expensive than human larynges. A novel dissection approach was created to maximize utility of a single cadaveric laryngeal specimen. Development of a laryngeal dissection manual facilitated a laryngeal dissection course. CONCLUSIONS: A laryngeal dissection educational course can be instituted with simple and relatively inexpensive modifications to an existing temporal bone laboratory. Canine larynges can be substituted for human larynges for a substantial cost savings without educational compromise. The educational methods demonstrated can be easily duplicated at other training sites.

Clinical practice guideline: hoarseness (dysphonia).

OBJECTIVE: This guideline provides evidence-based recommendations on managing hoarseness (dysphonia), defined as a disorder characterized by altered vocal quality, pitch, loudness, or vocal effort that impairs communication or reduces voice-related quality of life (QOL). Hoarseness affects nearly one-third of the population at some point in their lives. This guideline applies to all age groups evaluated in a setting where hoarseness would be identified or managed. It is intended for all clinicians who are likely to diagnose and manage patients with hoarseness. PURPOSE: The primary purpose of this guideline is to improve diagnostic accuracy for hoarseness (dysphonia), reduce inappropriate antibiotic use, reduce inappropriate steroid use, reduce inappropriate use of anti-reflux medications, reduce inappropriate use of radiographic imaging, and promote appropriate use of laryngoscopy, voice therapy, and surgery. In creating this guideline the American Academy of Otolaryngology-Head and Neck Surgery Foundation selected a panel representing the fields of neurology, speech-language pathology, professional voice teaching, family medicine, pulmonology, geriatric medicine, nursing, internal medicine, otolaryngology-head and neck surgery, pediatrics, and consumers. RESULTS: The panel made strong recommendations that 1) the clinician should not routinely prescribe antibiotics to treat hoarseness and 2) the clinician should advocate voice therapy for patients diagnosed with hoarseness that reduces voice-related QOL. The panel made recommendations that 1) the clinician should diagnose hoarseness (dysphonia) in a patient with altered voice quality, pitch, loudness, or vocal effort that impairs communication or reduces voice-related QOL; 2) the clinician should assess the patient with hoarseness by history and/or physical examination for factors that modify management, such as one or more of the following: recent surgical procedures involving the neck or affecting the recurrent laryngeal nerve, recent endotracheal intubation, radiation treatment to the neck, a history of tobacco abuse, and occupation as a singer or vocal performer; 3) the clinician should visualize the patient's larynx, or refer the patient to a clinician who can visualize the larynx, when hoarseness fails to resolve by a maximum of three months after onset, or irrespective of duration if a serious underlying cause is suspected; 4) the clinician should not obtain computed tomography or magnetic resonance imaging of the patient with a primary complaint of hoarseness prior to visualizing the larynx; 5) the clinician should not prescribe anti-reflux medications for patients with hoarseness without signs or symptoms of gastroesophageal reflux disease; 6) the clinician should not routinely prescribe oral corticosteroids to treat hoarseness; 7) the clinician should visualize the larynx before prescribing voice therapy and document/communicate the results to the speech-language pathologist; and 8) the clinician should prescribe, or refer the patient to a clinician who can prescribe, botulinum toxin injections for the treatment of hoarseness caused by adductor spasmodic dysphonia. The panel offered as options that 1) the clinician may perform laryngoscopy at any time in a patient with hoarseness, or may refer the patient to a clinician who can visualize the larynx; 2) the clinician may prescribe anti-reflux medication for patients with hoarseness and signs of chronic laryngitis; and 3) the clinician may educate/counsel patients with hoarseness about control/preventive measures. DISCLAIMER: This clinical practice guideline is not intended as a sole source of guidance in managing hoarseness (dysphonia). Rather, it is designed to assist clinicians by providing an evidence-based framework for decision-making strategies. The guideline is not intended to replace clinical judgment or establish a protocol for all individuals with this condition, and may not provide the only appropriate approach to diagnosing and managing this problem.

Cidofovir efficacy in recurrent respiratory papillomatosis: a randomized, double-blind, placebo-controlled study.

OBJECTIVES: We performed a prospective, double-blind, placebo-controlled, longitudinal adjuvant therapy trial to determine the efficacy of cidofovir in the treatment of severe recurrent respiratory papillomatosis (RRP). Although results of case series suggest that cidofovir may decrease the frequency and rapidity of papilloma regrowth, no blinded placebo-controlled studies have demonstrated efficacy. METHODS: Adults and children (n = 19) with aggressive RRP received either active drug (cidofovir) or placebo. When surgical intervention was needed, drug or placebo was injected into affected areas after surgical removal of disease. The following measures were made at baseline and at 2-month intervals for the course of 12 months: Derkay papilloma severity grading scale, Voice Handicap Index, Health-Related Quality of Life, and total number of procedures performed over 12 months. RESULTS: At 2- and 12-month follow-ups, there was a significant (p < .05) improvement in the Derkay Severity Score within the cidofovir and placebo groups, but no difference between groups, and no difference between groups in the number of procedures performed. Significant improvement was found in Voice Handicap Index scores in the cidofovir group at the 12-month follow-up. No differences were seen in Health-Related Quality of Life. CONCLUSIONS: A randomized, blinded, placebo-controlled trial is necessary in the study of RRP, because the natural history of the disease can include remissions and reactivations. We found a significant improvement in the Derkay Severity Score 12 months after the baseline assessment in patients treated with cidofovir. This effect, however, was also seen in the placebo group. Accordingly, we were unable to provide proof of efficacy of cidofovir in the treatment of RRP.

Clinical trials update from the European Society of Cardiology Congress in Vienna, 2007: PROSPECT, EVEREST, ARISE, ALOFT, FINESSE, Prague-8, CARESS in MI and ACUITY.

The Clinical Trials described in this article were presented at the Hotline and Clinical Trial Update Sessions of the European Society of Cardiology Congress held in September 2007 in Vienna, Austria. The sessions chosen for this article represent the scope of interest of Cardiovascular Drugs and Therapy. The presentations should be considered preliminary, as further analyses could alter the final publication of the results of these studies. PROSPECT evaluated echocardiographic criteria for optimal selection of patients with moderate to severe heart failure who may benefit from cardiac resynchronisation therapy, however concluded that no single echocardiographic measure can be recommended. EVEREST found that tolvaptan, a vasopressin V(2) antagonist, resulted in early weight reduction and improvement of dyspnoea in patients with acute heart failure, but lacked long term improvement. In ARISE, the anti-oxidant succinobucal did not affect the primary outcome in high risk cardiovascular patients, but improved the combination of cardiovascular death, myocardial infarction and stroke, and diabetic control in diabetics. ALOFT showed that the addition of the renin inhibitor aliskiren to an ACE inhibitor or ARB and a beta-blocker leads to favourable effects on neurohormonal actions in heart failure. FINESSE markedly improved coronary patency before PCI with half-dose reteplase/abciximab in STEMI patients, however without significantly improving short-term outcome. The Prague-8 Study evaluated whether routine clopidogrel administered >6 h pre-angiography would be a safe way to achieve therapeutic drug levels in case a follow-up intervention would be considered immediately, but appeared not justified because of bleeding complications. CARESS in MI showed that high risk patients with evolving STEMI who undergo thrombolytic therapy should undergo PCI early after the thrombolysis. Finally, the ACUITY trial found that in moderate or high risk Non ST elevation ACS patients triaged to PCI, coronary artery bypass graft (CABG) surgery, or medical management, bivalirudin, with or without associated GPIIb/IIIa inhibitor therapy, resulted in a marked reduction of bleeding at 30 days whilst preserving the ischemic and mortality benefit at 1 year follow up.

Toxic cure: Hyperfractionated radiotherapy with concurrent cisplatin and fluorouracil for Stage III and IVA head-and-neck cancer in the community.

PURPOSE: To evaluate efficacy and toxicity of the Duke University chemoirradiation regimen for locally advanced head-and-neck cancer in a regional community cancer center. METHODS AND MATERIALS: Between June 1998 and June 2002, 50 patients with Stage III or IVA squamous cell carcinoma of the head and neck were treated definitively with concurrent combined modality therapy (CMT). Patients received accelerated, hyperfractionated radiotherapy (AFRT), 1.2-1.25 Gy b.i.d., to a median prescribed dose of 70 Gy. Chemotherapy consisted of cisplatin 12 mg and fluorouracil 600 mg/m(2) daily for 5 consecutive days during Weeks 1 and 6, followed by two cycles after AFRT. Patients with N2-N3 neck disease (n = 21; 42%) were considered for neck dissection depending on their response to AFRT and chemotherapy. Twenty-nine patients with Stage III and IVA disease treated between 1991 and 1997 with definitive RT alone served as historical controls. RESULTS: Forty-nine patients (98%) in the CMT group completed the prescribed AFRT and 38 (76%) completed four cycles of chemotherapy. Three of 8 patients who underwent neck dissection had a pathologically complete response. The median follow-up for all patients was 23 months. The actuarial progression-free survival rate at 2 years was 75% for the CMT group vs. 40% (p <0.01) for the RT group. The overall survival rate was 80% and 43% (p <0.01), respectively, for the CMT and RT groups. Acute Radiation Therapy Oncology Group Grade 3 toxicities for the CMT group were mucosal (n = 50; 100%), skin (n = 9; 18%), and hematologic (n = 3; 6%). Late Grade 3-4 toxicities consisted of pharyngeal stricture (n = 7; 14%), laryngeal chondritis (n = 3; 6%), osteoradionecrosis (n = 2; 4%), and peripheral neuropathy (n = 1; 2%). CONCLUSION: This aggressive regimen of AFRT with concurrent cisplatin and fluorouracil with or without neck dissection is feasible in the community setting for patients with Stage III and IVA head-and-neck cancer. Early results indicated excellent survival, albeit with universal acute mucosal, and considerable, although acceptable, late toxicity.

Disorders of phonation in children.

Vocal disturbances in children are surprisingly common. Typical pathologic conditions differ, however, from those that are seen commonly in adults. Disturbances in the vibratory characteristic of the vocal folds cause dysphonia. The most common causes for dysphonia are infectious, anatomic, congenital, inflammatory, neoplastic, neurologic, or iatrogenic in nature. A child who presents with hoarseness demands a rapid and thorough assessment. Fine points during the history may provide the clinician with clues as to the correct etiologic category. Proper treatment requires an accurate diagnosis. Although some conditions are similar in the adult larynx, treatment of the pediatric larynx often differs. An understanding of the changing and growing pediatric larynx is necessary for treatment and satisfactory results.

Effect of neutral endopeptidase inhibition on the actions of adrenomedullin and endothelin-1 in resistance arteries from patients with chronic heart failure.

Adrenomedullin and endothelin are novel peptides that are produced in the blood vessel wall and have contrasting biologic actions. Both may play a pathophysiological role in atherosclerosis and chronic heart failure. It has also been suggested that both peptides may be metabolized by neutral endopeptidase and that pharmacological manipulation of this enzyme may be of therapeutic interest. We investigated the effect of thiorphan, a neutral endopeptidase inhibitor, on the vasodilator response to adrenomedullin and the vasoconstrictor response to endothelin in small resistance arteries taken from patients with heart failure caused by coronary heart disease. Small resistance arteries were dissected from gluteal biopsy samples and studied with wire myography. Thiorphan did not affect the vasodilator response to adrenomedullin in arteries preconstricted with norepinephrine. Maximal responses were 66% (SD 11%) and 72% (8%) in the absence and presence of thiorphan, respectively (n=8). The vasoconstrictor response to endothelin was also unaffected. The maximum vasoconstrictor responses in the absence and presence of thiorphan were 152% (11%) and 132% (12%), respectively (n=8). The values of corresponding -log concentrations of agonist required to effect a 50% response (pD(2)) were 8.52 (0.11) and 8.64 (0.15), respectively. We showed that the inhibition of neutral endopeptidase does not augment the vasodilator and vasoconstrictor activities of adrenomedullin and endothelin, respectively, in small resistance arteries from patients with chronic heart failure. This suggests that neutral endopeptidase inhibition, as a therapeutic strategy, will enhance neither the potentially desirable vascular actions of adrenomedullin nor the potentially unfavorable vascular effects of endothelin-1 in human cardiovascular disease states.

Impaired endothelial function in isolated human uremic resistance arteries.

BACKGROUND: Patients with chronic renal failure (CRF) face a markedly increased risk of cardiovascular death. CRF is frequently complicated by hypertension and changes in both the heart (left ventricular hypertrophy) and the vasculature (endothelial dysfunction and accelerated atherosclerosis). The mechanisms underlying changes in vascular function and specifically endothelial dysfunction are unclear. This present study therefore examined subcutaneous resistance artery function in vitro, comparing adult uremic patients and controls using wire myography. METHODS: Subcutaneous fat biopsies were obtained from 12 patients with CRF (median serum creatinine 735 micromol/L) at the time of renal transplantation or peritoneal dialysis catheter insertion, and from eight controls without renal disease at the time of abdominal surgery. Resistance arteries were mounted on a wire myograph. Their contractile ability was tested with high potassium depolarization, and endothelial integrity was tested by relaxation to acetylcholine. Cumulative concentration-response curves were then constructed for norepinephrine, endothelin-1, acetylcholine, and sodium nitroprusside (SNP). RESULTS: Following preconstriction with norepinephrine, vessels from uremic patients vasodilated less well to acetylcholine compared with vessels from controls [maximum % relaxation 77% (range 41, 97) vs. 98% (78, 100), P < 0.001]. The vasodilation to SNP was similar [95% (63, 100) vs. 94% (71, 100), P = 0.751]. There was a trend toward increased maximum pressure (kPa) achieved with both norepinephrine and endothelin-1 in vessels from uremic patients, and the contractions to both of these agents were more prolonged in the uremic vessels. CONCLUSIONS: The pattern of normal vasodilation to SNP but reduced vasodilation to acetylcholine is consistent with endothelial dysfunction due to impaired nitric oxide (NO) production in uremic vessels. Similar results have been demonstrated in vivo in uremia, one suggested mechanism being accumulation of endogenous inhibitors of NO synthase such as asymmetric dimethylarginine (ADMA). This in vitro study suggests that a short-lived circulating factor is not entirely responsible and that there may be an inherent abnormality in endothelial function in uremia, although the exact pathophysiology remains unclear. Endothelial dysfunction may predispose the patient to accelerated atherosclerosis and may be involved in the pathogenesis of hypertension in end-stage renal failure.