Articles: human.
-
Ont Health Technol Assess Ser · Jan 2009
Fenestrated endovascular grafts for the repair of juxtarenal aortic aneurysms: an evidence-based analysis.
Endovascular repair of abdominal aortic aneurysm (AAA) allows the exclusion of the dilated aneurismal segment of the aorta from the systematic circulation. The procedure requires, however, that the endograft extends to the healthy parts of the aorta above and below the aneurysm, yet the neck of a juxtarenal aortic aneurysm (JRA) is too short for a standard endovascular repair. Fenestrated endovascular aortic repair (f-EVAR) provides a solution to overcome this problem by enabling the continuation of blood flow to the renal and visceral arteries through holes or 'fenestrations' in the graft. These fenestrations are designed to match the ostial diameter of the renal and visceral arteries.There are three varieties fenestration, small, large, and scallop, and their location needs to be customized to fit the anatomy of the patient. If the device is not properly designed, if the alignment is inaccurate, or if the catheterization of the visceral arteries is not possible, the procedure may fail. In such cases, conversion to open surgery may become the only option as fenestrated endografts are not retrievable.It is recommended that a stent be placed within each small fenestration to the target artery to prevent shuttering of the artery or occlusion. Many authors have noted an increased risk of vessel occlusion in unstented fenestrations and scallops.Once placed in a patient, life-long follow-up at regular intervals is necessary to ensure the graft remains in its intended location, and that the components have adequate overlap. Should the need arise, routine follow-up allows the performance of timely and appropriate intervention through detection of events that could impact the long-term outcomes. ⋯ f-EVAR Studies versus OSR StudiesTechniqueNumber ofPatientsMean Age(Range), YearsAneurysm Diameter(Range),mmMean Duration ofFollow-up, Yearsf-EVAR(5 studies)27474 (72-75)63 (59-68)9.4-25.8OSR(7 studies)856:JRA: 675SRA: 136TAA: 4572 (67-78)62 (50-70)1-48JRA, Juxtarenal aortic aneurysm; SRA, Suprarenal aortic aneurysm; TAA, Thoracic aortic aneurysm MORTALITY OUTCOMES: The pooled estimate for 30-day mortality was 1.8% among the f-EVAR studies and 3.1% among the OSR studies that reported data for the repair of JRA separately. The pooled estimate for late mortality was 12.8% among the f-EVAR studies and 23.7% among the OSR studies that reported data for JRA separately. VISCERAL ARTERY EVENTS REPORTED IN F#ENTITYSTARTX02014;EVAR STUDIES: RENAL EVENTS DURING F-EVAR: A total of three main renal arteries and two accessory renal arteries became occluded during the procedure. These were all due to technical issues, except one accessory renal artery in which the artery was intentionally covered. One patient required open surgery following the procedure. RENAL EVENTS DURING THE FOLLOW-UP: A total of 12 renal arteries (12 patients) were found to be occluded during follow-up. In two patients, the same side accessory renal artery was also occluded. Four (1.5%) patients lost one kidney and five (2.3%) patients underwent dialysis, three (1.4%) of which became permanent. A total of 16 cases of renal artery stenosis (16 patients) occurred during follow-up. Eight of these were treated and eight were observed. Segmental renal infarcts were found in six patients but renal function was not impaired. MESENTERIC EVENTS DURING F-EVAR: Three mesenteric events occurred during the f-EVAR procedures resulting in two deaths. One patient developed bowel ischemia due to embolization of the superior mesenteric artery (SMA); this patient died 13 days after the procedure from multiorgan failure. One patient died eights days after the procedure from mesenteric ischemia and bowel perforation. The third SMA event occurred during surgery with subsequent occlusion in early follow-up. MESENTERIC EVENTS DURING FOLLOW-UP: During follow-up, five (1.8%) SMA occlusions/partial occlusions and one SMA stenosis were noted. Three of the five patients with SMA occlusion/partial occlusion remained asymptomatic and no further intervention was necessary. One patient underwent SMA bypass surgery and in two patients, the problem solved by SMA stenting. A summary of the outcomes reported in the f-EVAR and OSR studies is shown in Table ES-2. ES-2.Summary of Outcomes: Fenestrated Endovascular Graft Versus Open Surgical Repair for Treatment of Juxtarenal Aortic AneurysmOutcomef-EVAROSRPooled Estimate (Rate)30-day mortality1.83.1Late mortality12.823.7Permanent dialysis0-2.50-3.5Loss of kidney1.5No report of kidney loss Incidence of post-op renal insufficiency: 14.4%Mesentric ischemia3.32.9Aortic rupture00Post-op cardiac complications1.510.7Post-op pulmonary complications0.713.4Post-op GI complications0.75.9Aneurysm expansion1.40Secondary intervention (Non-endoleak)8.87.8EndoleakType I: 4Type 2: 16.8Type III: 1.8N/AEndoleak required treatmentType I: 2.9Type 2: 3.3Type III: 1.1Graft migration1.5N/AGraft separation0.7Duration (Mean)Operation time (min)240287Hospital stay (days)613 SUMMARY: Short- and medium-term results (up to 2 years) of f-EVAR for the repair of JRA showed that outcomes in f-EVAR series compare favourably with the figures for the OSR series; however, uncertainty remains regarding the long-term results. The following observations are based on low quality evidence. F-EVAR has lower 30-day mortality than OSR (1.8% vs. 3.1%) and a lower late-mortality over the period of time that patients have been followed (12.8% vs. 23.7%).There is a potential for the loss of target vessels during or after f-EVAR procedures. Loss of a target vessel may lead to loss of its respective end organ. The risk associated with this technique is mainly due to branch vessel ischemia or occlusion (primarily among the renal arteries and SMA). Ischemia or occlusion of these arteries can occur during surgery due to technical failure and/or embolization or it may occur during follow-up due to graft complications such as graft migration, component separation, or arterial thrombosis. The risk of kidney loss in this series of f-EVAR studies was 1.5% and the risk of mesenteric ischemia was 3.3%. In the OSR studies, the risk of developing renal insufficiency was 14.4% and the risk of mesenteric ischemia was 2.9%.F-EVAR has a lower rate of postoperative cardiac and pulmonary complications.Endoleak occurs in 22.5% of patients undergoing f-EVAR (all types) and about 8% of these require treatment. Most of the interventions performed to treat such endoleaks conducted using a minimally invasive approach.Due to the complexity of the technique, patients must be appropriately selected for f-EVAR, the procedure performed by highly experienced operators, and in centers with advanced, high-resolution imaging systems to minimize the risk of complications.Graft fenestrations have to be custom designed for each patient to fit and match the anatomy of their visceral arteries. Planning and sizing thus requires scrutiny of the target vessels with a high degree precision. This is important not only to prevent end organ ischemia and infarction, but to avoid prolonging procedures and subsequent adverse outcomes.Assuming the average cost range of FEVAR procedure is $24,395-$30,070 as per hospital data and assuming the maximum number of annual cases in Ontario is 116, the average estimated cost impact range to the province for FEVAR procedures is $2.83M-$3.49M annually.
-
Ont Health Technol Assess Ser · Jan 2009
Intrastromal corneal ring implants for corneal thinning disorders: an evidence-based analysis.
The purpose of this project was to determine the role of corneal implants in the management of corneal thinning disease conditions. An evidence-based review was conducted to determine the safety, effectiveness and durability of corneal implants for the management of corneal thinning disorders. The evolving directions of research in this area were also reviewed. SUBJECT OF THE EVIDENCE-BASED ANALYSIS: The primary treatment objectives for corneal implants are to normalize corneal surface topography, improve contact lens tolerability, and restore visual acuity in order to delay or defer the need for corneal transplant. Implant placement is a minimally invasive procedure that is purported to be safe and effective. The procedure is also claimed to be adjustable, reversible, and both eyes can be treated at the same time. Further, implants do not limit the performance of subsequent surgical approaches or interfere with corneal transplant. The evidence for these claims is the focus of this review. The specific research questions for the evidence review were as follows: SafetyCorneal Surface Topographic Effects:Effects on corneal surface remodellingImpact of these changes on subsequent interventions, particularly corneal transplantation (penetrating keratoplasty [PKP])Visual AcuityRefractive OutcomesVISUAL QUALITY (SYMPTOMS): such as contrast vision or decreased visual symptoms (halos, fluctuating vision)Contact lens toleranceFunctional visual rehabilitation and quality of lifePatient satisfaction:Disease Process:Impact on corneal thinning processEffect on delaying or deferring the need for corneal transplantation ⋯ In the MAS evidence review on intrastromal corneal ring implants, 66 reports were identified on the use of implants for management of corneal thinning disorders. Reports varied according to their primary clinical indication, type of corneal implant, and whether or not secondary procedures were used in conjunction with the implants. Implants were reported to manage post LASIK thinning and/or uncorrected refractive error and were also reported as an adjunctive intervention both during and after corneal transplant to manage recurrent thinning and/or uncorrected refractive error. (ABSTRACT TRUNCATED)
-
The Contact Heat Evoked Potential Stimulator (CHEPS) utilises rapidly delivered heat pulses with adjustable peak temperatures to stimulate the differential warm/heat thresholds of receptors expressed by Adelta and C fibres. The resulting evoked potentials can be recorded and measured, providing a useful clinical tool for the study of thermal and nociceptive pathways. Concurrent recording of contact heat evoked potentials using electroencephalogram (EEG) and functional magnetic resonance imaging (fMRI) has not previously been reported with CHEPS. Developing simultaneous EEG and fMRI with CHEPS is highly desirable, as it provides an opportunity to exploit the high temporal resolution of EEG and the high spatial resolution of fMRI to study the reaction of the human brain to thermal and nociceptive stimuli. ⋯ The results of this study demonstrate the feasibility of recording contact heat evoked potentials with EEG during continuous and simultaneous fMRI. The combined use of the two methods can lead to identification of distinct patterns of brain activity indicative of pain and pro-nociceptive sensitisation in healthy subjects and chronic pain patients. Further studies are required for the technique to progress as a useful tool in clinical trials of novel analgesics.
-
Expert Rev Pharmacoecon Outcomes Res · Dec 2008
Recommendations for the prevention and treatment of influenza using antiviral drugs based on cost-effectiveness.
Influenza is an acute respiratory disease that causes epidemics and pandemics in the human population of temperate regions. Influenza epidemics occur every year during the winter months, affecting approximately 10% of the population. The primary strategy for reducing the effect of influenza in the community is to vaccinate persons who are at risk or caring for high-risk individuals each year before seasonal increases in influenza virus circulation occur. ⋯ Based on the cost-effectiveness threshold of pound30,000 or $40,000 per QALY, antiviral therapies can be recommended for influenza treatment and post-exposure prevention in healthy and high-risk individuals and for seasonal prevention in high-risk individuals. Zanamivir, oseltamivir and amantadine have favorable cost-effectiveness ratios for these interventions, but amantadine should only be used in countries with a low prevalence of resistant virus. The stockpile of antiviral drugs should be maintained in developed countries because they are cost effective for the prevention and treatment of a possible influenza pandemic.
-
Evid Based Child Health · Dec 2008
Cochrane Review: Interventions for the interruption or reduction of the spread of respiratory viruses.
Viral epidemics or pandemics such as of influenza or severe acute respiratory syndrome (SARS) pose a significant threat. Antiviral drugs and vaccination may not be adequate to prevent catastrophe in such an event. ⋯ Interventions to interrupt or reduce the spread of respiratory viruses Although respiratory viruses usually only cause minor disease, they can cause epidemics. Approximately 10% to 15% of people worldwide contract influenza annually, with attack rates as high as 50% during major epidemics. Global pandemic viral infections have been devastating because of their wide spread. In 2003 the severe acute respiratory syndrome (SARS) epidemic affected ˜8,000 people, killed 780, and caused an enormous social and economic crisis. A new avian influenza pandemic caused by the H5N1 strain might be more catastrophic. Single measures (particularly the use of vaccines or antiviral drugs) may be insufficient to interrupt the spread.We found 51 studies including randomised controlled trials (RCTs) and observational studies with a mixed risk of bias.Respiratory virus spread might be prevented by hygienic measures around younger children. These might also reduce transmission from children to other household members. Implementing barriers to transmission, isolation, and hygienic measures may be effective at containing respiratory virus epidemics. There was limited evidence that (more uncomfortable and expensive) N95 masks were superior to simple ones. Adding virucidals or antiseptics to normal handwashing is of uncertain benefit. There is insufficient evaluation of global measures such as screening at entry ports and social distancing.