In This Edition
- Aspirin plus extended-release dipyridamole and clopidogrel provide similar outcomes in stroke.
- Traditional readings of bedside chest radiographs are insensitive in detecting intraatrial central venous catheter placement.
- Improved outcomes with bortezomib in myeloma treatment.
- ICD firings in cardiomyopathy patients are associated with worse outcomes.
- The clinical dehydration scale rapidly assesses the severity of dehydration in children.
- Liberal red blood cell transfusions may be harming patients.
- Five-year risk of colorectal neoplasia is low in patients with negative screening colonoscopy.
- Vital sign instability and oxygenation predict prognosis following hospitalization for community acquired pneumonia.
Is aspirin plus extended release dipyridamole more efficacious and safer than clopidogrel in preventing recurrent stroke?
Background: Recurrent stroke is a frequent (7% to 8% thrombotic stroke recurrence in first year) and disabling event after ischemic stroke. Multiple randomized trials demonstrate efficacy of anti-platelet agents for the prevention of recurrent stroke after non-cardioembolic stroke. However, direct comparisons and relative benefits of various antiplatelet agents are not well defined.
Study design: Randomized, double-blinded, two-by-two factorial design with intention-to-treat analysis.
Setting: A total of 20,333 patients from 695 centers in 35 countries, including the U.S.
Synopsis: This study directly compared aspirin plus extended-release dipyridamole to clopidogrel within the PRoFESS trial. A total of 20,333 patients were enrolled and followed up for a mean duration of 2.5 years. Eligible patients randomly were assigned to receive either 25 mg aspirin plus 200 mg extended-release twice a day, or clopidogrel 75 mg a day; and either telmisartan 80 mg once a day or placebo. Groups were similar at baseline.
The primary outcome of recurrent stroke was similar in both the aspirin plus extended-release dipyrimadole group and the clopidogrel group (9.0% vs. 8.8%). The composite secondary outcome of stroke, myocardial infarction or vascular death, and tertiary outcomes were similar in both groups. The trial showed statistical equivalence in the rates of recurrent stroke in the two groups.
Despite more frequent hemorrhagic strokes in the group receiving aspirin plus extended-release dipyridamole (4.1% vs. 3.6%), there was no significant difference in the risk of fatal or disabling stroke between both the groups.
Bottom line: Aspirin plus extended-release dipyridamole is equivalent to clopidogrel in the prevention of recurrent stroke, in terms of relevant efficacy and safety parameters.
Citation: Sacco RL, Diener H, Yusuf S, et.al. Aspirin and extended-release dipyridamole versus clopidogrel for recurrent stroke. N Engl J Med. 2008:359:1238-1251.
Background: Placement of central venous catheters is common, particularly in critical care settings. Correct placement is usually confirmed by bedside chest radiography. The recommended location of the distal catheter tip is superior to the superior vena cava and right atria junction. However, determining this landmark on traditional bedside chest radiographs is frequently inaccurate.
Study design: Prospective, blinded study.
Setting: University hospital in Germany.
Synopsis: The researchers enrolled 212 patients scheduled for elective cardiac surgery. Either left or right internal jugular vein central lines were placed via EKG guidance, and more precisely evaluated by transesophageal echocardiography. Bedside chest radiographs were performed within three hours of admission to the ICU.
The radiologists were able to detect between 40% and 60% of incorrect central venous catheter placements when compared to transesophageal echocardiography. The researchers concluded TC-distance (tip of catheter to carina) of greater than 55 mm on chest X-ray performed better (98% accurate) in the detection of intra-atrial catheter placement, compared to conventional judgment by attending (93% accurate) or resident (53% accurate) radiologists. Limitations of the study include the use of only one attending radiologist. Secondly, the chest radiographs and echocardiograms were not done simultaneously, allowing for possible movement of the catheters between studies.
Bottom line: A TC distance of greater than 55 mm on chest X-ray should be further investigated as an accurate method to detect intra-atrial central venous catheters.
Citation: Wirsing M, Schummer C, Neumann R, et al. Is traditional reading of the bedside chest radiograph appropriate to detect intra-atrial central venous catheter position? Chest. 2008;134:527-533.
Background: More than 50% of newly diagnosed myeloma patients are older than 65 and cannot receive optimal treatment with high-dose chemotherapy and stem-cell transplant. Previous trials have demonstrated patients with relapsed or refractory myeloma benefit from the administration of bortezomib, which sensitizes the myeloma cell lines to melphalan.
Study design: Randomized, open-label (unblinded) phase 3 study.
Setting: 151 centers, 22 countries in Asia, Europe, South and North America.
Synopsis: 682 patients with untreated multiple myeloma, who were ineligible for high-dose chemotherapy and stem cell transplant, were treated with bortezomib in combination with standard melphalan and prednisone, or melphalan and prednisone alone. The bortezomib group had improved partial or complete response (71% vs. 35%; NNT=3; p<0.001), increased median time to progression of disease (19.9 months vs. 13.1 months), and improved overall survival (87% vs. 78% over a 16-month median follow up; NNT=11; p=0.008). There were increased grade 3 adverse effects with the intervention, but no increase in grade 4 events or treatment related deaths compared to control. Limitations of the study include lack of blinding and involvement of the pharmaceutical company in data collection analysis, writing and editing of the manuscript.
Bottom line: Bortezomib is a valuable adjunct to standard treatment of multiple myeloma in patients over the age of 65 who may be ineligible for high-dose chemotherapy and stem cell transplant.
Citation: San Miguel JF, Schlag R, Khuageva NK, et al. Bortezomib plus melphalan and prednisone for the initial treatment of multiple myeloma. NEJM. 2008;359:906-917.
Does the occurrence of a shock increase the risk of death in cardiomyopathy patients with defibrillators?
Background: The SCD-HeFT trial, originally published in 2005, was instrumental in demonstrating the utility of defibrillators in the primary prevention of sudden cardiac deaths in patients with either ischemic or non-ischemic cardiomyopathy, NYHA class II or III, ejection fraction <35%, and no history of sustained ventricular tachycardia or fibrillation. This study re-examined the data derived from the SCD-HeFT trial to better understand the long-term prognosis of these patients with defibrillators who receive either appropriate shocks (ventricular fibrillation, sustained ventricular tachycardia), inappropriate shocks, or no shocks. Inappropriate shocks were defined as defibrillations due to supraventricular tachycardia, oversensing P or T waves as R waves, double counting of R waves, and artifact.
Study design: Retrospective cohort (analysis of patients randomized to implantable cardioverter-defibrillator (ICD) group in SCD-HeFT).
Setting: Multicenter trial.
Synopsis: The analysis demonstrated patients who received shocks were 11 times more likely to die compared with those who had no defibrillations (Hazard Ratio [HR]=11.3, p<0.001). These shocked patients were at more risk (HR=5.7, p<0.001) than those with inappropriate shocks (HR=2.0, p=0.002). Therefore, even inappropriate shocks themselves doubled the risk of death. Patients who received more than one shock, either appropriate or not, were at even higher odds of death (HR=8.3, p<0.001). The results highlight the higher mortality risk when patients with ICDs have received a shock (appropriate or inappropriate) and the need for further therapies to modify outcome in these patients.
Bottom Line: Appropriate or inappropriate defibrillations are associated with a poorer prognosis in patients with cardiomyopathy.
Citation: Poole JE, Johnson GW, Hellkamp AS, et al. Prognostic importance of defibrillator shocks in patients with heart failure. N Engl J Med. 2008(359):1009-1017.
Background: Despite the frequency and the associated cost of acute gastroenteritis (AGE) in the pediatric population, there is no unified scale to assess the severity of dehydration. The authors of this paper previously reported a clinical dehydration scale (CDS) and applied it prospectively in a new cohort of patients ages 1 month to 5 years.
Study design: Prospective, observational study.
Setting: Single, tertiary care emergency department (ED) in Canada.
Synopsis: The CDS score is based purely on the physical findings of the child, including a) general appearance, b) eyes, c) mucous membranes, and d) amount of tears. On a point system, the patient is placed in one of three categories: no dehydration, some dehydration, moderate/severe dehydration. The trial enrolled 205 children and the CDS was applied by the triaging nurse. The attending ED pediatricians were blinded from this assessment. The CDS was able to predict the length of stay (mean + SD: no dehyrdation 245 + 181 mins; some dehydration, 397 + 302 mins; mod/severe dehydration, 501 + 389 mins), need for intravenous rehydration (none, 15%; some, 49%; mod/severe, 80%), and frequency of emesis/diarrhea as reported by the parents (none, 8.4 + 7.7; some, 13 + 10.7; mod/severe, 30.2 + 14.8). Only five children were categorized in the moderate/severe dehydration category, which may limit the ability to generalize the scoring system to that group of patients.
Bottom line: The CDS is an easy to use and promising tool to assess the severity of illness, expected ED length of stay, and need for intravenous rehydration in children with acute gastroenteritis.
Citation: Goldman RD, Friedman JN, Parkin PC. Validation of the clinical dehydration scale for children with acute gastroenteritis. Pediatrics. 2008;122(3):545-549.
Background: Historically, medical and surgical critical care patients liberally were transfused with little prospective evidence to support this approach. However, recent evidence has led to the use of a more-restricted transfusion threshold.
Study design: Systematic review and meta-analysis of cohort studies evaluating the effect of red blood cell (RBC) transfusion on patient outcomes.
Setting: Data sources include MEDLINE, Embase, and Cochrane databases.
Synopsis: The 45 cohort studies, including more than 272,000 patients, were selected due to focus on outcome measures, such as mortality, multiorgan dysfunction, acute respiratory distress syndrome, and infections. Primary studies were then placed into one of three categories: benefits outweigh the risk, neutral, or risks outweigh the benefit. Forty-two of these studies found the risks outweigh the benefits; two were neutral; and only one sub-study (in elderly patients with acute myocardial infarctions) suggested benefit outweighs the risk.
Although a systematic review of cohort studies has inherent limitations, the overwhelming direction of the results suggests statistically significant harm due to liberal transfusion practices (Summary Odd Ratios [OR] for a) death, OR = 1.69; b) infection, OR = 1.88; and c) Acute Respiratory Distress Syndrome, OR = 2.5). Due to the observational nature of the cohort studies, one might suspect RBC transfusions could simply reflect patient severity of illness. Thus, the harm suggested by the more liberal transfusion standards could just reflect the fact these patients carried a worse prognosis due to their respective illnesses.
Bottom Line: The preponderance of evidence suggests liberal transfusion practice is associated with increased morbidity and mortality of ICU patients. When considering RBC transfusions, the risks and benefits to each individual patient should be considered carefully.
Citation: Marik PE, Corwin HL. Efficacy of red blood cell transfusion in the critically ill: a systematic review of the literature. Crit Care Med. 2008; 36(9);2667-2674.
What is the appropriate frequency of rescreening for patients with initial screening colonoscopies negative for adenomas?
Background: Colonoscopy is the preferred primary screening method for the detection of colorectal cancer and precancerous polyps. Data suggest colonoscopy may be performed too frequently and for inappropriate indications.
Study design: Retrospective cohort study.
Setting: Seven sites in central Indiana.
Synopsis: In this study of 2,436 persons with no adenomas on baseline screening colonoscopies, 1,256 of them (51.6%) were rescreened a mean of 5.34 + 1.34 years later. No cancers were found on rescreening. One or more adenomas were found in 201 persons (16.0%). Nineteen advanced adenomas were found in 16 persons (1.3%). Patients in this study were relatively young (mean age at baseline was 56.7 years). Men were more likely than women to have adenomas (RR 1.88; 95% CI 1.42-2.51) and to have advanced adenomas (RR 3.31; 95% CI 1.02-10.8).
Limitations included a small cohort sample size, as well as incomplete information on persons who did not follow up with the five-year examination. Also, there is uncertainty about the clinical significance of advanced adenomas.
Bottom Line: Among persons previously screened with colonoscopy who have no colorectal adenomas, the five-year risk of detecting an advanced adenoma is extremely low (1.3%), supporting a rescreening interval of more than five years after a normal colonoscopy. Men have greater risk, and may deserve a shorter interval screening.
Citation: Imperiale TF, Glowinski EA, Lin-Cooper C, et al. Five-year risk of colorectal neoplasia after negative screening colonoscopy. N Engl J Med. 2008;359:1218-1224.
Can validated discharge instability criteria predict mortality or readmission within 30 days of hospital discharge for community acquired pneumonia (CAP)?
Background: Prior prospective cohort data have delineated instability criteria utilizing vital sign criteria at hospital discharge for CAP. However, guidelines for determining patient readiness for discharge remain largely unstudied.
Study design: Prospective, observational cohort study.
Setting: A single, non-urban teaching hospital in Spain.
Synopsis: In this study, 870 adults with CAP were evaluated following discharge. Abnormal oxygenation and vital signs were utilized to calculate an instability score. Criteria for instability were defined as temperature >37.5° C, heart rate <100, respiratory rate >24, systolic blood pressure (SBP) <90 (or diastolic blood pressure, DBP <60), and oxygen saturation <90% (or PaO2 <60).
Of all the instability criteria, only low oxygenation predicted readmission at 30 days (Hazard Ratio [HR] 1.4, p=0.03). However, mortality was significantly increased when instability criteria of temperature (HR 4.5, p=0.04), blood pressure (HR 2.6, p=0.02), respiratory rate (HR 2.4, p=0.03), or oxygenation (HR 2.4, p=0.03) were met. Elevated heart rate was not found to predict death.
The authors assigned each of the significant instability criteria a score of one or two (based on the weight of its hazard ratio), with respiratory rate, low blood pressure, and low oxygenation each assigned one point, and temperature assigned two points. Patients with an instability score of two or more had a six-fold increased risk of death (HR 5.8; 95%, p=0.0001). The negative predictive value (NPV) of an instability score less than two was very helpful (NPV=98%) in identifying patients with low mortality risk; however, the positive predictive value (PPV) of an instability score >2 is not necessarily helpful (PPV=13%) clinically.
Bottom line: Patients with a temperature >37.5° C or any combination of RR >24, SBP <90 (or DBP <60), and SpO2 <90% (or Pa02 <60) are at increased risk of death. Identifying a low instability score is most helpful in clinical practice.
Citation: Capelastegui A, Espana P, Bilbao A, et al. Pneumonia: criteria for patient instability on hospital discharge. Chest. 2008;34:595-600.