Detection rate and outcome of colonic serrated epithelial changes in patients with ulcerative colitis or Crohn's colitis.

BACKGROUND: Chronic ulcerative colitis (CUC) and colonic Crohn's disease (CD) increase colorectal neoplasia (CRN) risk. While sessile serrated polyp (SSP) is a known cancer precursor, serrated epithelial changes (SEC) are of uncertain prevalence and neoplastic risk. AIM: To assess the serrated lesion detection rates in CUC and CD and documented incidence of subsequent CRN in a retrospective, single-centre cohort study. METHODS: Patients were identified by a central diagnostic index and pathology review confirmed SEC, SSP, CUC and CD diagnoses from 2006-12. Matched controls were identified from among all CUC and CD patients having colonoscopy during the second half of the time period. All were followed for incident CRN, estimated by the Kaplan-Meier method. RESULTS: Between 2006 and 2012, 79 SEC and 10 SSP cases were identified. Detection rates were estimated to be 10/1000 and 2/1000 patients, for SEC and SSP respectively, among 4208 unique CUC or CD patients having colonoscopy from 2010-12. With only 10 cases, SSP patients were not further analysed. Cumulative incidence of subsequent CRN at 1 and 3 years was 12% (95% CI, 0-30%) and 30% (3-57%), respectively, in SEC patients compared to 4% (0-12%) and 9% (0-23%), respectively, in CUC or CD controls (P = 0.047, log-rank). However, this statistical difference was not significant after patients were stratified for history of prior or synchronous dysplasia (P = 0.09). CONCLUSIONS: Serrated epithelial changes and sessile serrated polyps are uncommonly detected by colonoscopy in chronic ulcerative colitis and Crohn's disease patients. Histology with changes of serrated epithelium may be associated with risk of subsequent colorectal neoplasia, however further studies are needed to explore this relationship.

Stool DNA testing for the detection of colorectal neoplasia in patients with inflammatory bowel disease.

BACKGROUND: Current approaches to the detection of colorectal neoplasia associated with inflammatory bowel disease (IBD-CRN) are suboptimal. AIM: To test the feasibility of using stool assay of exfoliated DNA markers to detect IBD-CRN. METHODS: This investigation comprised tissue and stool studies. In the tissue study, gene sequencing and methylation assays were performed on candidate genes using tissue DNA from 25 IBD-CRNs and from 25 IBD mucosae without CRN. Mutations on p53, APC, KRAS, BRAF or PIK3CA genes were insufficiently informative, but several aberrantly methylated genes were highly discriminant. In the stool study, we evaluated candidate methylated genes (vimentin, EYA4, BMP3, NDRG4) in a prospective blinded study on buffered stools from 19 cases with known IBD-CRN and 35 age- and sex-matched IBD controls without CRN. From stool-extracted DNA, target genes were assayed using quantitative allele-specific real-time target and signal amplification method. RESULTS: IBD-CRN cases included 17 with ulcerative colitis (UC) and two with Crohn's disease (CD); nine had cancer and 10 had dysplasia. Controls included 25 with UC and 10 with CD. Individually, BMP3, vimentin, EYA4 and NDRG4 markers showed high discrimination in stools with respective areas under the ROC curve of 0.91, 0.91, 0.85 and 0.84 for total IBD-CRN and of 0.97, 0.97, 0.95 and 0.85 for cancer. At 89% specificity, the combination of BMP3 and mNDRG4 detected 9/9 (100%) of CRC and 80% of dysplasia, 4/4 (100%) of high grade and 4/6 (67%) of low grade. CONCLUSION: These findings demonstrate the feasibility of stool DNA testing for non-invasive detection of colorectal neoplasia associated with inflammatory bowel disease.

Regression analysis for comparing protein samples with 16O/18O stable-isotope labeled mass spectrometry.

MOTIVATION: Using stable isotopes in global proteome scans, labeled molecules from one sample are pooled with unlabeled molecules from another sample and subsequently subjected to mass-spectral analysis. Stable-isotope methodologies make use of the fact that identical molecules of different stable-isotope compositions are differentiated in a mass spectrometer and are represented in a mass spectrum as distinct isotopic clusters with a known mass shift. We describe two multivariable linear regression models for (16)O/(18)O stable-isotope labeled data that jointly model pairs of resolved isotopic clusters from the same peptide and quantify the abundance present in each of the two biological samples while concurrently accounting for peptide-specific incorporation rates of the heavy isotope. The abundance measure for each peptide from the two biological samples is then used in down-stream statistical analyses, e.g. differential expression analysis. Because the multivariable regression models are able to correct for the abundance of the labeled peptide that appear as an unlabeled peptide due to the inability to exchange the natural C-terminal oxygen for the heavy isotope, they are particularly advantageous for a two-step digestion/labeling procedure. We discuss how estimates from the regression model are used to quantify the variability of the estimated abundance measures for the paired samples. Although discussed in the context of (16)O/(18)O stable-isotope labeled data, the multivariable regression models are generalizable to other stable-isotope labeled technologies.

Exercise echocardiography for the prognostic stratification of patients with low pretest probability of coronary artery disease.

PURPOSE: The aim of this study was to determine whether exercise echocardiography provides incremental data for risk stratification of patients with a low pretest probability of coronary artery disease. PATIENTS AND METHODS: The study included patients referred for exercise echocardiography whose probability of coronary artery disease was 25% or less. We calculated an exercise wall motion score index (on a 1-5 scale), an indicator of the extent and severity of exercise-induced abnormalities. The primary outcomes of the study were subsequent cardiac events (cardiac death and nonfatal myocardial infarction). RESULTS: We studied 571 men and 1047 women; their mean (+/- SD) age was 55 +/- 13 years. During a median follow-up of 3 years, there were 19 cardiac events (6 cardiac deaths and 13 nonfatal myocardial infarctions); an additional 37 patients underwent coronary revascularization. In a multivariate analysis of clinical, exercise electrocardiographic, and echocardiographic parameters, exercise wall motion score index (hazard ratio [HR] = 2.1 per 0.5 units; 95% confidence interval [CI]: 1.3 to 3.4), and age (HR = 2.0 per decade; 95% CI: 1.2-2.8) were independently associated with the risk of cardiac events. Although exercise echocardiographic variables contributed significantly (P = 0.01) to a model of the risk of adverse events, only 9 (47%) of the 19 patients with cardiac events were identified by an abnormal exercise echocardiogram. CONCLUSION: Among patients with low pretest probability of coronary artery disease by clinical criteria, exercise echocardiography identifies some, but not all, patients at risk of future events. Because of the low event rate, routine application of exercise echocardiography in a patient with a low pretest probability does not appear to be cost-effective and therefore cannot be recommended.

Contrast dobutamine stress echocardiography: clinical practice assessment in 300 consecutive patients.

In this study we compared non-contrast imaging with contrast imaging of the left ventricle during dobutamine stress echocardiography (DSE). Wall segment visualization, image quality, and confidence of interpretation were determined with and without the use of intravenous Optison, a second-generation echocardiographic contrast agent, in 300 consecutive patients undergoing rest and peak DSE. At rest and at peak stress, the percentage of wall segments visualized, image quality, and confidence of interpretation were better with contrast compared with non-contrast imaging. No significant decrease was seen in wall segment visualization, image quality, or confidence of interpretation from rest to peak stress in images obtained with contrast, unlike the images obtained without contrast from rest to peak stress. The use of the intravenous echocardiographic contrast agent Optison during DSE significantly improved wall segment visualization and image quality at rest and at peak stress, resulting in improved confidence of interpretation.

Prognostic stratification of diabetic patients by exercise echocardiography.

OBJECTIVES: The aim of this study was to assess the incremental value of exercise echocardiography for the risk stratification of diabetic patients. BACKGROUND: There are currently insufficient outcome data in diabetic patients to define the role of stress echocardiography as a prognostic tool. METHODS: We studied the prognostic value of exercise echocardiography in 563 patients with diabetes mellitus (mean age 64 +/- 11 years, 336 men) and known or suspected ischemic heart disease (IHD). RESULTS: Cardiac events occurred in 50 patients (cardiac death in 23 and nonfatal myocardial infarction [MI] in 27) during a median follow-up period of three years. Event rate was lower in patients with normal as compared to those with abnormal exercise echocardiography at one year (0% vs. 1.9%), three years (1.8% vs. 11.9%), and five years (7.6% vs. 23.3%), respectively (p = 0.0001). Patients with multivessel distribution of echocardiographic abnormalities had the highest event rate (2.9% at one year, 15.2% at three years, and 32.8% at five years). In an incremental multivariate analysis model, exercise echocardiography increased the chi-square of the clinical and exercise ECG model from 29 to 44.8 (p = 0.0001). CONCLUSIONS: Exercise echocardiography provides incremental data for risk stratification of diabetic patients with known or suspected IHD. Patients with a normal exercise echocardiogram have a low event rate. Patients with multivessel distribution of exercise echocardiographic abnormalities are at the highest risk of cardiac events, as one-third of these patients experience cardiac death or nonfatal MI during the five years following exercise echocardiography.

Prognostic value of exercise echocardiography in patients after coronary artery bypass surgery.

To assess the prognostic value of exercise echocardiography in patients with prior coronary artery bypass surgery, follow-up was obtained in 718 patients (591 men [82%] and 127 women [18%], aged 67 +/- 9 years) who underwent clinically indicated exercise echocardiography 5.7 +/- 4.7 years after coronary bypass surgery. Resting wall motion abnormalities were present in 479 patients (67%). New or worsening wall motion abnormalities developed with exercise in 366 patients (51%). During a median follow-up of 2.9 years, cardiac events included cardiac death in 36 patients and nonfatal myocardial infarction in 40 patients. The addition of the exercise echocardiographic variables, abnormal left ventricular end-systolic volume response and exercise ejection fraction to the clinical, resting echocardiographic and exercise electrocardiographic model provided incremental information in predicting cardiac events (chi-square 37 to chi-square 42, p = 0.02) and cardiac death (chi-square 38 to chi-square 43, p <0.02). Exercise echocardiography provides prognostic information in patients after coronary artery bypass surgery, incremental to clinical, rest echocardiographic, and exercise electrocardiographic variables.

Prognostic value of exercise echocardiography in 2,632 patients > or = 65 years of age.

OBJECTIVES: We sought to determine the prognostic value of exercise echocardiography in the elderly. BACKGROUND: Limited data exist regarding the prognostic value of exercise testing in the elderly, a population which may be less able to exercise and is at increased risk of cardiac death. METHODS: Follow-up (2.9 +/- 1.7 years) was obtained in 2,632 patients > or = 65 years who underwent exercise echocardiography. RESULTS: There were 1,488 (56%) men and 1,144 (44%) women (age 72 +/- 5 years). The rest ejection fraction was 56 +/- 9%. Rest wall motion abnormalities were present in 935 patients (36%). The mean work load was 7.7 +/- 2.3 metabolic equivalents (METs) for men and 6.5 +/- 1.9 METs for women. New or worsening wall motion abnormalities developed with stress in 1,082 patients (41%). Cardiac events included cardiac death in 68 patients and nonfatal myocardial infarction in 80 patients. The addition of the exercise electrocardiogram to the clinical and rest echocardiographic model provided incremental information in predicting both cardiac events (chi-square = 77 to chi-square = 86, p = 0.003) and cardiac death (chi-square = 71 to chi-square = 86, p < 0.0001). The addition of exercise echocardiographic variables, especially the change in left ventricular end-systolic volume with exercise and the exercise ejection fraction, further improved the model in terms of predicting cardiac events (chi-square = 86 to chi-square = 108, p < 0.0001) and cardiac death (chi-square = 86 to chi-square = 99, p = 0.004). CONCLUSIONS: Exercise echocardiography provides incremental prognostic information in patients > or = 65 years of age. The best model included clinical, exercise testing and exercise echocardiographic variables.

Dysphagia without endoscopically evident disease: to dilate or not?

OBJECTIVES: It is not known whether patients with symptoms of dysphagia but normal upper endoscopy benefit from empiric esophageal dilation. The aim of this prospective study was to determine whether patients with solid food dysphagia and normal upper endoscopy have symptomatic benefit from empiric dilation using a through-the-scope balloon. METHODS: Patients who were seen for complaints of solid food dysphagia and who had normal endoscopic examinations at our institution from 1998 through 1999 were identified. Those patients who had agreed before sedation to participate in the study, if eligible, were randomized to either sham or balloon dilation using an 18-mm through-the-scope balloon at the time of esophagogastroduodenoscopy. All potentially eligible patients who had given provisional consent completed a dysphagia questionnaire and a 10-cm visual analog dysphagia scale before endoscopy. Follow-up questionnaires were completed on day 1 and at 3 months and 6 months after the procedure. The primary endpoint of the study was the patient's self-assessment of difficulty swallowing, based on the questionnaires. RESULTS: A total of 83 patients met the study criteria and were randomized to balloon dilation (n = 43) or sham (n = 40). The two groups were comparable in age, sex, severity of baseline dysphagia. and use of antireflux medication. Improvement in dysphagia comparing sham to balloon on day 1 was 66% versus 67% (p = 0.99); at 3 months it was 82% versus 76% (p = 0.56); and at 6 months it was 84% versus 73% (p = 0.38). There were no reported complications in either group. CONCLUSION: The data from this prospective randomized, controlled study do not support the practice of empiric dilation in patients with symptoms of dysphagia without an endoscopically evident cause of dysphagia.

Fecal calprotectin levels predict colorectal inflammation among patients with chronic diarrhea referred for colonoscopy.

OBJECTIVE: Chronic diarrhea is a relatively common condition with multiple diverse etiologies. Stool testing may serve as a diagnostic aid to discriminate the presence or absence of organic pathology, such as colorectal inflammation. Calprotectin (a leukocyte-derived protein) and hemoglobin can be measured quantitatively from stool and represent candidate inflammation biomarkers. The aim of this study was to assess and compare the screening performance of fecal calprotectin and fecal hemoglobin among colonoscopy referral patients with chronic diarrhea of unknown origin or chronic colitis of unknown activity. METHODS: All subjects were identified prospectively and each submitted a single stool sample before purgation. Fecal calprotectin (PhiCal; Nycomed Pharma, Oslo, Norway) and fecal hemoglobin (HemoQuant; Mayo Medical Laboratories, Rochester, MN) assays were performed in separate laboratories by masked technicians. Colonoscopic and histological findings served as criterion standards for establishing the presence or absence of colorectal inflammation. RESULTS: Among 110 subjects who provided complete fecal assay data, 29 (26%) had and 81 (74%) did not have colorectal inflammation. Increased fecal calprotectin levels were significantly (p = 0.0001) associated with the presence of colorectal inflammation, whereas fecal hemoglobin levels were not (p = 0.61). Direct comparison of the fecal assays revealed that calprotectin was a more sensitive biomarker for colorectal inflammation at all specificity levels (p = 0.0001). CONCLUSIONS: In this study of colonoscopy referral patients, colorectal inflammation was reflected by fecal calprotectin but not by fecal hemoglobin levels. Assay of fecal calprotectin holds promise as a triage tool to identify inflammatory causes of chronic diarrhea.

Transthoracic Doppler echocardiographic comparison of left internal mammary grafts to left anterior descending coronary artery with ungrafted right internal mammary arteries in patients with and without myocardial ischemia by dobutamine stress echocardiography.

To characterize Doppler flow patterns of the grafted left internal mammary artery (LIMA) in patients with and without dobutamine stress induced wall motion abnormalities in the graft distribution, we studied 29 patients who underwent coronary artery bypass surgery using LIMA grafts to the left anterior descending coronary artery (LAD). The ungrafted right internal mammary artery (RIMA) was used as a control. RIMA Doppler flow pattern was predominantly systolic in all patients. In patients without ischemia in the LAD distribution, LIMA flow was predominantly diastolic. In patients with ischemia, LIMA flow was predominantly systolic. In the grafted LIMA, a ratio of diastolic to systolic time-velocity integral of > 1.5 best showed absence of ischemia in the graft distribution. In summary, characterization of the Doppler flow pattern in the internal mammary arteries is feasible. In the grafted LIMA, ratios of diastolic to systolic flow are less in patients with an ischemic response in the subtended vascular bed than in those without ischemia.

Colorectal cancer screening by detection of altered human DNA in stool: feasibility of a multitarget assay panel.

BACKGROUND & AIMS: Assay of altered DNA exfoliated into stool represents an intriguing approach to screen for colorectal neoplasia, but multiple markers must be targeted because of genetic heterogeneity. We explored the feasibility of a stool assay panel of selected DNA alterations in discriminating subjects with colorectal neoplasia from those without. METHODS: Freezer-archived stools were analyzed in blinded fashion from 22 patients with colorectal cancer, 11 with adenomas > or =1 cm, and 28 with endoscopically normal colons. After isolation of human DNA from stool by sequence-specific hybrid capture, assay targets included point mutations at any of 15 sites on K-ras, p53, and APC genes; Bat-26, a microsatellite instability marker; and highly amplifiable DNA. RESULTS: Analyzable human DNA was recovered from all stools. Sensitivity was 91% (95% confidence interval, 71%-99%) for cancer and 82% (48%-98%) for adenomas > or =1 cm with a specificity of 93% (76%-99%). Excluding K-ras from the panel, sensitivities for cancer were unchanged but decreased slightly for adenomas to 73% (39%-94%), while specificity increased to 100% (88%-100%). CONCLUSIONS: Assay of altered DNA holds promise as a stool screening approach for colorectal neoplasia. Larger clinical investigations are indicated.

The relationship between elution time and eluate volume using the Ultra-TechneKow DTE technetium-99m generator.

OBJECTIVE: The new Ultra-TechneKow Dry Ship Top Elute 99mTc generator (UTK-DTE generator; Mallinckrodt Medical, Inc., St. Louis, MO) was devised to facilitate fractionated elution with an ergonomically designed elution shield. Fractionation is accomplished traditionally by visually observing the eluted volume through 2 layers of leaded glass windows located in a lighted elution shield and generator auxiliary shield. The goal of our study was to use elution time to determine the endpoint for obtaining the required volume of 99mTc-eluate from a UTK-DTE generator. METHODS: After triplicate elution at several predetermined elution times, the initial weight of the evacuated collecting vial was subtracted from the total weight after elution to determine the elution volume. RESULTS: A quadratic relationship was established between the eluate volume (v, mL) and elution time (t, s) (v = 0.3594 + 0.1889 t - 0.0009 t2). This equation is suitable for use with the 10-mL elution vial. This formula may not be accurate for the first elution since the UTK-DTE generator is a dry-column generator when shipped. The following elution times were calculated for some commonly eluted volumes: 2 mL (9 s), 4 mL (22 s), 5 mL (28 s), 7 mL (45 s), and 10 mL (88 s). CONCLUSION: Our calculated elution time method can be used to predict the eluate volume from a UTK-DTE generator.

Operation for partial atrioventricular septal defect: a forty-year review.

BACKGROUND: We describe the long-term outcome of repair of partial atrioventricular septal defect by determining the rates of survival, reoperation, and occurrence of left atrioventricular valve regurgitation, left atrioventricular valve stenosis, left ventricular outflow tract obstruction, and arrhythmia. METHODS: We studied 334 patients who underwent repair of partial atrioventricular septal defect before 1995. RESULTS: The 30-day and 5-, 10-, 20-, and 40-year survival were 98%, 94%, 93%, 87%, and 76%, respectively. Closure of the left atrioventricular valve cleft (P =. 03) and age less than 20 years at operation (P <.001) were associated with better survival. Reoperation was performed for 38 patients (11%). Repair of residual/recurrent left atrioventricular valve regurgitation or stenosis was the most common reason for reoperation. Left ventricular outflow tract obstruction occurred in 36 patients, and 7 patients underwent reoperation to relieve this obstruction. Supraventricular arrhythmias were observed in 58 patients (16%) after the operation. Supraventricular arrhythmias increased with increasing age at primary operation (P =.001). Complete atrioventricular block occurred in 9 patients (3%). Permanent pacemakers were implanted in 11 patients. CONCLUSIONS: Long-term survival after repair of partial atrioventricular septal defect is good. It is important to close the cleft in the left atrioventricular valve. Reoperation for persistent or recurrent left atrioventricular valve malfunction and relief of left ventricular outflow tract obstruction is necessary in approximately 11% of patients.

Assessment of cardiac risk before nonvascular surgery: dobutamine stress echocardiography in 530 patients.

OBJECTIVE: This study evaluated the incremental value of dobutamine stress echocardiography (DSE) for assessment of cardiac risk before nonvascular surgery. BACKGROUND: Limited information exists regarding the preoperative assessment of cardiac risk in patients with known or suspected coronary artery disease who are to undergo nonvascular surgery. METHODS: All patients (303 men, 227 women) who underwent DSE before nonvascular surgery and did not sustain an intervening event (coronary revascularization or cardiac event) were studied. Clinical, electrocardiographic and rest and stress echocardiographic variables were evaluated to identify predictors of postoperative cardiac events. RESULTS: Events occurred in 6% of patients: 1 cardiac death and 31 nonfatal myocardial infarctions. All of these patients had inducible ischemia on DSE (sensitivity 100%, specificity 63%). Multivariate predictors of postoperative events in patients with ischemia were history of congestive heart failure (p = 0.006; odds ratio = 4.66; confidence interval 1.55 to 14.02) and ischemic threshold less than 60% of age-predicted maximal heart rate (p = 0.0001; odds ratio 7.002; confidence interval 2.79 to 17.61). Clinical variables of Eagle's index identified 21% of patients as low, 68% as intermediate and 11% as high risk preoperatively; the postoperative event rates were 3%, 6%, and 14%, respectively. Dobutamine stress echocardiography identified 60% of patients as low (no ischemia), 32% as intermediate (ischemic threshold 60% or more) and 8% as high risk (ischemic threshold < 60%); postoperative event rates were 0%, 9% and 43%, respectively. CONCLUSIONS: In this population of patients with known or suspected coronary artery disease evaluated before nonvascular surgery, DSE had incremental value over clinical, electrocardiographic and rest echocardiographic variables for identifying patients at low, intermediate and high risk for postoperative cardiac events. Ischemia occurring at less than 60% of age-predicted maximal heart rate identified patients at highest risk.

Calcific constrictive pericarditis: is it still with us?

BACKGROUND: The presence of pericardial calcification on a plain radiograph strongly suggests constrictive pericarditis in patients with heart failure. However, calcific constrictive pericarditis is considered rare in the United States since tuberculosis incidence has decreased, and doubt has therefore been raised about the importance of this radiologic finding in modern cardiovascular practice. OBJECTIVE: To determine the clinical and prognostic significance of pericardial calcification on radiography in patients with constrictive pericarditis. DESIGN: Retrospective cohort study. SETTING: Tertiary referral center. PATIENTS: A consecutive series of 135 patients (mean age +/- SD, 56 +/- 16 years) who from 1985 through 1995 had constrictive pericarditis confirmed surgically (n = 133) or by autopsy (n = 2). Patients were divided into two groups: those with pericardial calcification on chest radiography (group I) and those without (group II). MEASUREMENTS: Clinical and diagnostic findings were compared in both groups, and outcome was compared in 132 patients who had pericardiectomy. RESULTS: Pericardial calcification was seen in 36 patients (27%). The cause of constrictive pericardial disease was indeterminate in 67% of patients in group I and in 21% of patients in group II (P < 0.001). Patients in group I had had symptoms for a longer period and were more likely to have pericardial knock, larger atrial size, and atrial arrhythmia. Significantly more perioperative deaths were seen in group I, but incidence of late survival and incidence of noncalcific disease were similar in both groups. CONCLUSIONS: Pericardial calcification is a common finding in patients with constrictive pericarditis. It is often associated with idiopathic disease and other markers of disease chronicity and is an independent predictor of increased perioperative mortality rates.

Evaluation of macroaggregated albumin particle sizes for use in pulmonary shunt patient studies.

OBJECTIVE: To assess commercial macroaggregated albumin (MAA) reagent kits for compliance with particle-size parameters needed for proper clinical evaluation of pulmonary shunts (right-to-left). DESIGN: Comparative trial. SETTING: Nuclear pharmacy (laboratory setting). PATIENTS AND OTHER PARTICIPANTS: Not applicable. INTERVENTIONS: Minimally, 90% of the particles contained within an MAA reagent kit should be within the 10 to 90 microns range with minimal variation in particle size distribution and as few small particles (i.e., < 10 microns) as possible. Five separate vials from five commercial brands of MAA reagent kits were obtained, and 500 to 517 particles were analyzed for each sample. An additional study was performed on one of the MAA reagent kit brands, using five vials from each of five different lot numbers to determine the variability between lots. MAIN OUTCOME MEASURES: Long axis (maximum, micron), short axis (minimum, micron), and the area (micron 2) of each MAA particle. RESULTS: One MAA brand had the lowest percentage of unacceptable MAA particle sizes and maintained consistent particle sizes between vials. However, the same MAA reagent kit brand showed that only two of five lots had a low percentage of MAA particle sizes below the 10-micron limit. CONCLUSION: Particle sizes varied among the five different brands of MAA reagent kits, as did different lots of the best-performing kit. This variability in particle sizes may affect the accuracy and reproducibility of pulmonary shunt patient studies.

Evaluation of an alternative radiochemical purity testing method for technetium-99m sestamibi.

OBJECTIVE: Our study evaluated the accuracy and reliability of 3 radiochemical purity (RCP) measurement methods of 99mTc-sestamibi. A regular-sized (1.0 cm x 9.0 cm) Whatman 31 ET Chr paper strip (regular 31 ET) also was included in our evaluation because of its ease in handling. METHODS: The miniaturized and regular 31 ET methods were compared with the standard RCP testing method (aluminum oxide-coated plastic thin-layer chromatography [TLC] plate, with > or = 95% ethanol as the developing solvent). A total of 30 experimental runs were performed in triplicate (n = 90) over an RCP range of 82%-98%. The 99mTc-sestamibi preparations were reconstituted purposely to ensure that 50% of the tested samples had RCP values below the 90% limit. RESULTS: The evaluated RCP ranges were 89.9% +/- 6.3%, 91.0% +/- 3.8%, and 91.4% +/- 4.3% for the TLC, miniature 31 ET, and regular 31 ET methods, respectively (n = 30 each). A strong correlation was found between the TLC and miniature 31 ET methods (r = 0.92), as well as between the TLC and regular 31 ET methods (r = 0.94). Both alternative methods tended to overestimate RCP value as determined by the TLC method, especially in an RCP range below 95%. This resulted in a false-positive rate of 27% for the miniature 31 ET method and 33% for the regular 31 ET method. The test/retest reliability was 99% for both the TLC and regular 31 ET methods, and 91% for the TLC and miniature 31 ET methods. CONCLUSION: The miniature and regular 31 ET methods produced a high false-positive rate, which makes them unacceptable for the determination of RCP value of 99mTc-sestamibi.

Constrictive pericarditis in the modern era: evolving clinical spectrum and impact on outcome after pericardiectomy.

BACKGROUND: The clinical spectrum of constrictive pericarditis (CP) has been affected by a change in incidence of etiological factors. We sought to determine the impact of these changes on the outcome of pericardiectomy. METHODS AND RESULTS: The contemporary spectrum of CP in 135 patients (76% male) evaluated at the Mayo Clinic from 1985 to 1995 was compared with that of a historic cohort. Notable trends were an increasing frequency of CP due to cardiac surgery and mediastinal radiation and presentation in older patients (median age, 61 versus 45 years). Perioperative mortality decreased (6% versus 14%, P = 0.011), but late survival was inferior to that of an age- and sex-matched US population (57+/-8% at 10 years). The long-term outcome was predicted independently by 3 variables in stepwise logistic regression analyses: (1) age, (2) NYHA class, and most powerfully, (3) a postradiation cause. Of 90 late survivors in whom functional class could be determined, functional status had improved markedly (2.6+/-0.7 at baseline versus 1.5+/-0.8 at latest follow-up [P<0.0001]), with 83% being free of clinical symptoms. CONCLUSIONS: The evolving profile of CP, with increasingly older patients and those with radiation-induced disease in the past decade, significantly affects postoperative prognosis. Long-term results of pericardiectomy are disappointing for some patient groups, especially those with radiation-induced CP. By contrast, surgery alleviates or improves symptoms in the majority of late survivors.