Effect of rotavirus vaccination programme on trends in admission of infants to hospital for intussusception.

BACKGROUND: Studies have reported a temporal association between a first dose of rotavirus vaccine (Rotashield) and infant intussusception. We investigated the effect of Rotashield vaccination use on intussusception admissions in ten US states. METHODS: We analysed electronic databases containing 100% hospital discharge records for 1993-99 from ten US states, where an estimated 28% of the birth cohort had received Rotashield (based on manufacturer's net sales data). We examined records of infants admitted to hospital (<365 days old) with any mention of intussusception (International Classification of Diseases, ninth revision, clinical modification code 560.0). Excess admissions for intussusception during the period of Rotashield availability (October 1998 to June 1999) were estimated by direct comparison with the corresponding period of October 1997 to June 1998 (before Rotashield was available) and with adjustment for secular trends during 1993-98 by Poisson regression. FINDINGS: Hospital admission for intussusception among infants younger than 365 days of age during the Rotashield period compared with previously was 4% lower (10 cases) by direct comparison and 10% lower (27 cases) by trend comparison, corresponding to a negative population attributable risk. Among infants aged 45-210 days (target age range for a first Rotashield dose), we estimated an increase in intussusception admissions of 1% (one excess admission) by direct comparison and 4% (4.6 excess admissions) by trend comparison, corresponding to a population attributable risk range of one excess admission in 66000-302000. INTERPRETATION: We found no evidence of increased infant intussusception admissions during the period of Rotashield availability. The total intussusception admission risk attributable to Rotashield was substantially lower than previous estimates based on studies focusing on the immediate postvaccination weeks.

Hepatitis C in asymptomatic blood donors.

Among 248 asymptomatic blood donors positive for antibody to hepatitis C virus (anti-HCV) enrolled in a long-term prospective study, 86% had chronic HCV infection and 14% appeared to have recovered as assessed by serial determinations of serum alanine aminotransferase (ALT) levels and HCV RNA by polymerase chain reaction. Established parenteral risk factors for HCV transmission were identified in 75% of donors. In addition, there was a strong independent association between HCV positivity and cocaine snorting, suggesting that shared snorting devices may be a covert route of parenteral transmission. Ear piercing in males was also significantly associated with transmission. There was no evidence for sexual spread. Although the majority of HCV carriers had both biochemical and histological evidence of chronic viral hepatitis, the extent of liver injury was generally mild. Among a larger population of 280 HCV RNA-positive donors, 17% had repeatedly normal ALT levels, 45% had levels that did not exceed twice, and only 22% had levels that exceeded five times the upper limit of the normal range. Among 81 patients who underwent liver biopsy, only 13% had evidence of severe hepatitis (8%) or cirrhosis (5%), despite a duration of infection that generally exceeded 15 years. No severe histological lesions were observed in blood donors with chronic HCV infection who had repeatedly normal ALT levels. In both donors and blood recipients, the frequency of severe morbidity or mortality related to HCV infection was less than 10% during the first two decades of infection. Further long-term studies are required to see if the progression to severe outcomes continues to accrue at this slow pace or whether it accelerates during subsequent decades.

Estimation of time since exposure for a prevalent cohort.

In natural history studies of human immunodeficiency virus type 1 (HIV-1) infection a substantial proportion of participants are seropositive at time of enrollment in the study. These participants form a prevalent subcohort. Estimation of the unknown times since exposure to HIV-1 in the prevalent subcohort is of primary importance for estimation of the incubation time of AIDS. The subset of the cohort that tested negative for antibody to HIV-1 at study entry and was observed to seroconvert forms the incident subcohort that provides longitudinal data on markers of maturity (that is, duration) of infection. We use parametric life table regression models incorporating truncation to describe the conditional distribution (imputing model) of the times since seroconversion given a vector of the markers of maturity. Using the fitted model and the values of the markers of maturity of infection provided by the seroprevalent subcohort at entry into the study, we can impute the unknown times since seroconversion for the prevalent subcohort. We implement multiple imputation based on a model-robust estimate of the covariance matrix of parameters of the imputing model to provide confidence intervals for the geometric mean of the time since seroconversion in the prevalent subcohort, and to compare maturity of infection of cohorts recruited in different cities. The accuracy of imputation is further validated by comparisons of imputation-based estimates of AIDS incubation distribution in the seroprevalent subcohort with more direct estimates obtained from the seroincident subcohort.

Factors associated with prevalent human immunodeficiency virus (HIV) infection in the Multicenter AIDS Cohort Study.

Interviews regarding medical history, life-style, specific drug taking and sexual activities, and physical examinations were administered to 4,955 homosexual men who volunteered for the Multicenter AIDS Cohort Study in Baltimore, Chicago, Los Angeles, and Pittsburgh. Overall, the prevalence of antibodies to human immunodeficiency virus (HIV) in these men was 38.0%. The factor most strongly associated with prevalent HIV infection according to a multiple logistic regression model was rectal trauma, a composite variable which included receptive anal fisting, enemas before sex, reporting of blood around the rectum, and the observation of scarring, fissures or fistulas on rectal examination. Receptive anal intercourse also was strongly associated with HIV infection in the model. The multivariate relative odds for HIV antibody positivity was 7.72 for the highest level of rectal trauma and 3.04 for receptive anal intercourse. Symptoms reported to occur in some persons who subsequently develop acquired immunodeficiency syndrome (AIDS) were frequent among HIV seropositive men (12.9%) but were reported in 8.4% of seronegative men as well. Generalized lymphadenopathy was observed significantly more often in seropositive men (48.8%) compared with seronegative men (11.4%). The prevalence of HIV antibodies was inversely related to the number of T-helper cells and directly related (to a lesser extent) to the number of T-suppressor cells. The results suggest that disruption of the rectal mucosa provides access by HIV to the blood stream and to specific immunologic cells. Since symptoms and generalized lymphadenopathy were often reported among seronegative men, they probably also occur among some seropositive men not currently progressing to AIDS.

Acute coronary events associated with percutaneous transluminal coronary angioplasty.

Acute coronary events reported in patients enrolled in the NHLBI PTCA Registry were analyzed. Data were collected on 3,079 patients from 105 contributing centers. Coronary vascular events (dissection, occlusion, spasm, embolism, perforation or rupture) or ischemic events (MI or prolonged angina) occurred in 418 patients (13.6%). Major complications (MI), emergency surgery or death) occurred in 280 patients (67%) with acute coronary events. The most frequent events were prolonged angina, which occurred in 211 (6.8%), and MI, in 170 (5.5%). Coronary dissection, occlusion and spasm each occurred in approximately 5% of patients. Coronary embolism, perforation and rupture were rare (less than 0.2% for each). Dissection and occlusion each had a high frequency (greater than 80%) of associated major complications. A substantially lower incidence of major complications occurred in patients with isolated coronary spasm (18%) or prolonged angina (35%). Clinical and angiographic predictors for overall and specific events were identified. Coronary events occurred more frequently in women and patients with unstable angina. Eccentric lesions were associated with a higher rate of coronary events, and event rates were lower with single discrete lesions than with other types of lesions. The frequency of any coronary event, MI, prolonged angina and coronary spasm each decreased with increasing experience with PTCA. The frequency of dissection and occlusion did not change with experience.

Role of percutaneous transluminal coronary angioplasty in the treatment of unstable angina. Report from the National Heart, Lung, and Blood Institute Percutaneous Transluminal Coronary Angioplasty and Coronary Artery Surgery Study Registries.

The acute and long-term consequences of PTCA performed in patients with unstable angina was determined in 442 patients with 1-vessel CAD who were enrolled in the NHLBI PTCA Registry. These patients were compared with 214 similar patients in the PTCA Registry with stable angina and with 330 patients with unstable angina from the NHLBI CASS Registry who underwent CABG. The 3 groups had similar baseline characteristics. The immediate angiographic success after PTCA was not different between patients with stable and those with unstable angina. The in-hospital mortality rate was 0.9% for the PTCA group with unstable angina and 0.47% for the PTCA group with stable angina. The combined 18-month mortality and MI rate was low in both groups (10.8 and 9.5%, respectively). No differences were observed in the mortality and MI rates between patients with unstable angina treated surgically or with PTCA. Both revascularization procedures markedly reduced symptoms of angina. Ninety-two percent of the PTCA group reported improvement in their angina, whereas 80% of the surgical group had a reduction in angina (p less than 0.05). The results from this observational study suggest that PTCA can be performed as safely and successfully in patients with unstable angina as in those with stable angina. PTCA compares favorably with CABG in patients with unstable angina in that the procedure is associated with low mortality and morbidity rates, while marked improvement in symptoms can be expected. Thus, PTCA could be considered an alternative to CABG in patients with unstable angina who have the appropriate anatomic characteristics.

In-hospital mortality rate in the National Heart, Lung, and Blood Institute Percutaneous Transluminal Coronary Angioplasty Registry.

Twenty-nine patients died among the first 3,079 patients enrolled in the NHLBI PTCA Registry. The overall morality rate was 0.9%; the mortality rate was 0.8% in patients with 1-vessel CAD, 1.0% in those with multivessel CAD (excluding left main CAD), and 3.8% in those with left main CAD (p less than 0.01). The in-hospital morality rate was significantly higher among women (p less than 0.01), in patients older than 60 years, in patients with previous CABG (p less than 0.01), the presence of left main CAD, (p less than 0.01), in patients who required dilatation of a vein graft stenosis (p less than 0.05), and in patients who had had angina for longer than 6 months (p less than 0.01).

Emergency coronary bypass surgery after coronary angioplasty: the National Heart, Lung, and Blood Institute's Percutaneous Transluminal Coronary Angioplasty Registry experience.

The frequency and outcome of emergency CABG for complications of PTCA in the NHLBI PTCA Registry were analyzed. Emergency surgery was performed in 202 patients (6.6%). The most frequent indications for emergency operation were coronary dissection in 46%, coronary occlusion in 20%, prolonged angina in 14% and coronary spasm in 11%. Emergency surgery was most often necessary in patients in whom lesions could not be reached or traversed, but more than 25% of patients who required emergency surgery had initially successful dilatation followed by abrupt reclosure of the vessel. The mortality rate with emergency CABG was 6.4%, and nonfatal MI occurred in 41% of patients, with Q waves developing in approximately 60% of patients with MI. However, 53% of patients managed with emergency CABG for severe ischemic events with PTCA did not have evidence of MI or die and had an uncomplicated postoperative course. No baseline clinical predictors of emergency surgery were identified. Lesion eccentricity was associated with a significant increase in frequency of emergency operation, and the incidence of emergency surgery declined with increasing experience with PTCA.

Exercise, electrocardiographic and functional responses after percutaneous transluminal coronary angioplasty.

Exercise testing after successful PTCA showed improved cardiac functional status on examination of electrocardiographic and symptomatic responses, myocardial perfusion and global and regional left ventricular function. Sixty-six patients were studied before and after persistently successful PTCA. Follow-up studies an average of 8 months after the successful procedure showed an incidence of abnormal testing of only 7% using both electrocardiographic and subjective symptomatic criteria during treadmill studies and no abnormal studies with thallium scintigraphy. Radionuclide cineangiography demonstrated similar left ventricular ejection fractions at rest before and after PTCA, but an improvement of 9 +/- 10% (p less than 0.001) in the exercise ejection fraction at follow-up. However, 52% of patients with paired data still had an abnormal radionuclide cineangiographic study after successful PTCA, raising the question of the presence of subclinical ischemia or a false-positive result.

Return to work after coronary angioplasty: a report from the National Heart, Lung, and Blood Institute Percutaneous Transluminal Coronary Angioplasty Registry.

Employment status was analyzed in 2,250 patients enrolled at 65 clinical centers in the NHLBI PTCA Registry. Patients were classified into 3 groups depending on the outcome of PTCA. In 63.6%, PTCA was successful without MI or CABG (Group A); in 25.3%, PTCA was unsuccessful and was followed by CABG (Group B); and in 11.1%, PTCA was unsuccessful and was followed by medical therapy alone (Group C). At entry, 68.3% of all patients were employed full- or part-time. The clinical characteristics of the 3 groups were different. Patients in Group C had a higher incidence of previous MI and previous CABG. In addition, patients in Group C had a significantly decreased baseline employment rate compared with those in Group A. At a mean follow-up of 1.5 years, there was a small but similar decrease in the percentage employed full- or part-time in all groups. Employment status also was analyzed in a subset of 1,150 patients working full- or part-time at baseline and aged 60 years or younger, who would be expected to have the highest return to work rates. At a mean follow-up of 1.4 years, 81 to 86% of patients remained working irrespective of the outcome of PTCA. However, patients with successful PTCA returned to work significantly sooner. The occurrence of chest pain during follow-up in these patients was an important predictor of return to work, irrespective of the outcome of dilatation. In patients with chest pain during follow-up, only 77% were working, compared with 90% of patients who had not had chest pain.

Baseline characteristics of patients in the National Heart, Lung, and Blood Institute Percutaneous Transluminal Coronary Angioplasty Registry.

The efficacy of PTCA was evaluated in several subgroups of patients. Of special clinical interest were the comparisons between subgroups of patients with multivessel disease vs 1-vessel disease, unstable angina vs stable angina, older age vs younger age, and female sex vs male sex. As a prerequisite for such comparisons, baseline characteristics of patients in the subgroups were examined. Compared with the subgroup with 1-vessel CAD, the subgroup with multivessel CAD had more elderly patients (age 65 years and older) and more of these patients had previous MI or CABG. PTCA was more often unsuccessful in patients with multivessel CAD because of inability to pass the catheter across the lesion. The subgroup of women tended to be older than men, and more women had severe and unstable angina, although fewer had multivessel CAD, previous MI or previous CABG. The PTCA success rate was 5% lower in women because of a greater frequency of inability to pass the lesion. Compared with younger patients, older patients had a higher prevalence of severe angina, multivessel CAD and lesions with larger diameters. The older patients had a 5% lower PTCA success rate, once again because of a greater frequency of inability to pass the lesion. The learning experience with PTCA was measured by the overall success rate as well as by the rate of ability to pass the lesion and the rate of dilating it once it was passed. These rates improved significantly by the investigators' case accumulations and independently by calendar year. Multivariate prediction of crossing the lesion and of overall success showed that favorable lesion characteristics and increasing physician experience were more important than the patient characteristics just discussed, although both female sex and multivessel CAD remained significant independent risk factors.

Percutaneous transluminal coronary angioplasty (PTCA) in patients with relative contraindications: results of the National Heart, Lung, and Blood Institute PTCA Registry.

The effects of relative contraindications on the immediate results of PTCA were investigated in 1,939 patients, and on long-term results in 998 patients with isolated stenosis of 1 coronary artery. Immediate results subjected to analysis were: success rate, major complications (coronary occlusion, MI and death) and emergency CABG. The analysis of long-term results included: status of angina pectoris, occurrence of MI, restenosis, repeat PTCA, CABG and death. Unstable angina and previous MI had no negative effects on immediate results, whereas a significantly lower success rate was noted in patients with angina for more than 1 year compared to patients with angina of shorter duration (p less than 0.05) and patients older than 60 years compared with younger patients (p less than 0.01). During follow-up, patients with unstable angina had higher CABG rate (p less than 0.01); the other relative clinical contraindications to PTCA did not exert adverse effects. Angiographically, there was a lower immediate success rate in patients with nonproximal stenosis (p less than 0.001) and in patients with calcium in the affected artery (p less than 0.01) and at the site of stenosis (p less than 0.001). Patients with tubular or diffuse stenoses had similar success rates but higher rates of complications, excluding death, than those with discrete stenoses (p less than 0.01). Patients with eccentric stenoses had a lower success rate and a higher rate of complications and emergency CABG than patients with concentric stenoses (p less than 0.001 for all 3 variables).(ABSTRACT TRUNCATED AT 250 WORDS)

Percutaneous transluminal coronary angioplasty (PTCA) in the elderly patient: experience in the National Heart, Lung, and Blood Institute PTCA Registry.

Because CABG results in a significantly higher morbidity and prolonged hospitalization in the older patient group, PTCA is an attractive alternative for providing myocardial revascularization in the small group of older patients with appropriate lesions for dilation. This analysis of the results of PTCA in 370 older patients in the NHLBI PTCA Registry reveals that PTCA can be performed with acceptably low mortality and morbidity. Therefore, PTCA may offer an alternative to CABG in the highly selected symptomatic older patient.