Biomedical subjects

W C Hop

Publications and source records attributed to W C Hop.

At least 109 records · Page 6Linked to original sources

PubMed1999

Sampling of exhaled nitric oxide in children: end-expiratory plateau, balloon and tidal breathing methods compared.

The aim of this study was to compare exhaled nitric oxide concentrations obtained during controlled slow exhalation, presently considered as the method of choice, with two sampling methods that are easily performed by children: blowing air into a balloon and tidal breathing through a mouthpiece. One hundred and one well controlled, stable allergic asthmatic children (median age 11.7 yrs) performed the following tasks in duplicate: 1) exhalation from total lung capacity through a mouthpiece against a resistor with a standardized flow rate of 20% of the subject's vital capacity per second, using a biofeedback system; 2) a single deep exhalation into an NO-impermeable mylar balloon; and 3) tidal breathing through a low resistance mouthpiece over 2 min. NO was measured using a chemiluminescence analyser. Twenty-nine children (29%) were not able to perform a constant-flow exhalation of at least 3 s. All children performed the balloon and tidal breathing methods without difficulty. NO concentrations (means +/-SEM) were 5.3+/-0.2 parts per billion (ppb) at the end-expiratory plateau, 5.2+/-0.3 ppb in balloons (intraclass correlation coefficient (r(i)) = 0.73) and 8.0+/-0.4 ppb during tidal breathing (p<0.001, r(i) = 0.53 compared to plateau values). Mean values of NO during tidal breathing increased significantly with time, suggesting increasing contamination with nasal air. It was concluded that, in asthmatic children, the end-expiratory plateau concentration of nitric oxide during exhalation at 20% of the vital capacity per second is similar to the values obtained with the balloon method, with satisfactory agreement, but differs from values obtained during tidal breathing. The balloon method is cheap, simple and offers the interesting possibility to study exhaled nitric oxide in young children independently of the presence of a nitric oxide analyser.

Adolescent↗

PubMed1999

Hickman catheter-related infections in neutropenic patients: insertion in the operating theater versus insertion in the radiology suite.

PURPOSE: To determine the influence of microbial air quality during Hickman catheter insertion in the operating theater versus insertion in the radiology suite on the incidence of catheter-related infections (CRIs). PATIENTS AND METHODS: Hemato-oncologic patients with prolonged neutropenia on antimicrobial prophylaxis were entered onto the study. Catheters were inserted by experienced radiologists under sonographic and fluoroscopic guidance. RESULTS: Forty-eight Hickman catheters in 39 patients were inserted (23 in the operating theater, 25 in the radiology suite). CRIs were seen in 16 catheters (33%; six per 1,000 catheter days; eight in each group). Local infections were found in nine catheters (22%; six in the operating theater v three in the radiology suite; not significant [NS]), catheter-related bacteremia was found in 10 (29%; three in the operating theater v seven in the radiology suite; NS). Coagulase-negative staphylococci (CoNS) caused all CRIs. Despite early vancomycin therapy, 11 (69%; four in the operating room group v seven in the radiology suite group; NS) of the catheters with CRIs had to be removed prematurely. At 90 days after insertion, catheter survival was 78% and 60% (NS) for the operating room and radiology suite, respectively. Multivariate analysis showed that neutropenia increased the CRI risk 20-fold (P =.004) and was strongly related to premature catheter removal owing to infection (relative risk = 11.9; P =.009). Neutropenia on the day of insertion was also significantly correlated with CRI (P =.04) and premature catheter removal owing to infection (P =.03). Serial cultures of blood, exit site, and catheter hub did not predict the development of CRI. CONCLUSION: The high incidence of Hickman CRI caused by CoNS was not associated with insertion location (operating theater v radiology suite). Neutropenia, including neutropenia on the day of insertion, was a significant risk factor for CRI and infection-related catheter removal.

Adult↗

PubMed1998

Prognostic value of minimal residual disease in acute lymphoblastic leukaemia in childhood.

BACKGROUND: Sensitive techniques for detection of minimal residual disease (MRD) at degrees of one leukaemic cell per 10(3)-10(6) cells (10(-3)-10(-6)) during follow-up of children with acute lymphoblastic leukaemia (ALL) can provide insight into the effectiveness of cytotoxic treatment. However, it is not yet clear how information on MRD can be applied to treatment protocols. METHODS: We monitored 240 patients with childhood ALL who were treated according to national protocols of the International BFM Study Group. 60 patients relapsed and the patients in continuous complete remission (CCR) had a median event-free follow-up of 48 months. Bone-marrow samples were collected at up to nine time points during and after treatment. Standardised PCR analysis of patient-specific immunoglobulin and T-cell receptor gene rearrangements and TAL1 deletions were used as targets for semiquantitative estimation of MRD. Amount of MRD was classed as 10(-2) or more, 10(-3), and 10(-4) or less. FINDINGS: MRD negativity at the various follow-up times was associated with low relapse rates (3-15% at 3 years), but five-fold to ten-fold higher relapse rates (39-86% at 3 years) were found in MRD-positive patients. The distinct degrees of MRD appeared to have independent prognostic value (p [trend]<0.001) at all separate time points, especially at the first two time points (at the end of induction treatment and before consolidation treatment). At these two time points a high degree of MRD (> or = 10(-2)) was associated with a three-fold higher relapse rate when compared with patients with a low degree of MRD (< or = 10(-4)). At later time points (including the end of treatment) even a low degree of MRD was associated with a poor outcome. Positivity in patients in CCR after treatment was rare (< 1%). With the combined MRD information from the first two follow-up time points, it was possible to recognise three different risk groups--55 (43%) were in a low-risk group and had a 3-year relapse rate of only 2% (95% CI 0.05-12%); 19 (15%) were in a high-risk group and had a relapse rate of 75% (55-95%); and 55 (43%) were in an intermediate-risk group and had a 3-year relapse rate of 23% (13-36%). INTERPRETATION: Our collaborative MRD study shows that monitoring patients with childhood ALL at consecutive time points gives clinically relevant insight into the effectiveness of treatment. Combined information on MRD from the first 3 months of treatment distinguishes patients with good prognoses from those with poor prognoses, and this helps in decisions whether and how to modify treatment.

Antineoplastic Combined Chemotherapy Protocols↗

PubMed1998

Longitudinal evaluation of cytogenetic aberrations in prostatic cancer: tumours that recur in time display an intermediate genetic status between non-persistent and metastatic tumours.

Only limited data are available on chromosomes specifically involved in prostatic tumour progression. This study has evaluated the cytogenetic status of primary prostatic carcinomas, local tumour recurrences, and distant metastases, representing different time points in prostatic tumour progression. Interphase in situ hybridization (ISH) was applied with a set of (peri) centromeric DNA probes, specific for chromosomes 1, 7, 8 and Y, to routinely processed tissue sections of 73 tumour specimens from 32 patients. Longitudinal evaluation was possible in 11 cases with local recurrence and nine cases with distant metastases. The remaining 12 patients showed no evidence of local recurrence or distant metastasis after radical prostatectomy on follow-up (mean 60.5 months) and served as a reference. Numerical aberrations of at least one chromosome were found in 27 per cent of the local recurrences and 56 per cent of the distant metastases. In decreasing order of frequency, +8, +7, and -Y were observed in the recurrences and +8, +7, -Y, and +1 in the distant metastases. Evaluation of the corresponding primary tumour tissue of the recurrence group showed numerical aberrations in 45 per cent of cases. The aberrations found were, in decreasing order of frequency, -Y, +7, and +8. In the concomitant primary tumour tissue of the distant metastasis group, numerical aberrations were detected in 67 per cent of cases. The aberrations most frequently encountered were +8, -Y, followed by +7. In four cases, a concordance was found between the primary tumour and its recurrence or distant metastasis. Discrepancies might have been caused by cytogenetic heterogeneity. Comparison of the primary tumour tissue of the reference, the recurrence, and the distant metastasis groups showed a significant increase for the percentage of cases with numerical aberrations (Ptrend = 0.02). Likewise, a trend was seen for gain of chromosome 7 and/or 8 (Ptrend < 0.05). The number of DNA aneuploid tumours also increased in these different groups (Ptrend = 0.03). These data suggest that cancers which recur in time display an intermediate position between tumours of disease-free patients and metastatic cancers.

Adenocarcinoma↗

PubMed1998

Subclinical hepatic encephalopathy impairs daily functioning.

Subclinical hepatic encephalopathy (SHE) is assumed to have a negative effect on patients' daily functioning; therefore, treatment is recommended. However, no studies have been performed that document the clinical relevance of SHE. We performed a study in which the prevalence of SHE was determined in 179 outpatients with cirrhosis using two psychometric tests (Number Connection Test Part A [NCT-A] and the Digit Symbol Test [DGT]) and automated analysis of the electroencephalogram (EEG). SHE was defined by the presence of at least one abnormal psychometric test and/or abnormal slowing of the EEG. The influence of cirrhosis and SHE on patients' daily functioning was assessed using the Sickness Impact Profile (SIP) questionnaire. The distribution of SIP scores of the patients with cirrhosis differed from the reference scores of the general population. Patients with cirrhosis and SHE (n = 48) reported significantly more impairment in all 12 scales of the SIP, in the psychosocial subscore, the physical subscore, as well as in the total SIP score, compared with cirrhotic patients without SHE (n = 131). Multivariate analysis taking into account severity of liver disease (Child-Pugh score), presence of varices, and alcoholic etiology, showed that SHE independently was related to a diminished total SIP score. The reproducibility of the SIP was high when the test was repeated after a 3-month period. We conclude that SHE implies impaired daily functioning and warrants attempts at treatment.

Adolescent↗

PubMed1998

Clinical outcome of anterior overlapping external anal sphincter repair with internal anal sphincter imbrication.

UNLABELLED: Fecal incontinence caused by overt anterior sphincter defects sustained during childbirth is usually treated by a delayed overlapping repair of the external anal sphincter. However, an obstetric trauma is frequently associated with disruption of the perineal body and loss of the distal rectovaginal septum. Data regarding a combined repair, consisting of restoration of the rectovaginal septum and perineal body, overlapping external anal sphincter repair, and imbrication of the internal anal sphincter, are scanty. PURPOSE: This prospective study was aimed at the following: 1) evaluating the clinical outcome of such an anterior anal repair in patients with fecal incontinence caused by obstetric trauma; 2) comparing the functional results with those obtained in a historical group of patients who underwent a conventional direct sphincter repair. METHODS: During the period between 1973 and 1989, 24 female patients (median age, 44 (range, 28-67) years) with fecal incontinence underwent direct sphincter repair (Group I). During the period between 1989 and 1994, a consecutive series of 31 female patients (median age, 46 (range, 23-78) years) with fecal incontinence underwent anterior anal repair (Group II). RESULTS: At two years of follow-up, continence had been restored in 15 patients (63 percent) in Group I, whereas restoration of continence was successful in 21 patients (68 percent) in Group II. CONCLUSION: The more complex anterior anal repair fails to confer clinical benefit compared with the rather simple direct sphincter repair.

Adult↗

PubMed1998

Prognostic importance of gram-negative intestinal colonization preceding pancreatic infection in severe acute pancreatitis. Results of a controlled clinical trial of selective decontamination.

OBJECTIVES: To establish, firstly, whether gram-negative (re)-colonization of the gut leads to an increased risk of gram-negative pancreatic infections and whether this event is time-related and, secondly, whether the difference in the quantity and quality of micro-organisms colonizing the digestive tract influences morbidity and mortality. DESIGN: Prospective analysis of the results of systematic semi-quantitative cultures of several body areas taken from patients with severe acute pancreatitis, during a controlled multicenter trial of adjuvant selective decontamination. SETTING: Surgical intensive care units of 16 hospitals. PATIENTS: A total of 2,159 semi-quantitative cultures from the oropharynx, rectum and pancreatic tissues taken from 90 patients were analyzed. INTERVENTIONS: Surveillance cultures from the oropharynx and rectum were taken on admission and repeated twice weekly and from the (peri)-pancreatic devitalized tissues (i. e. necrosis) at every relaparotomy and from drainage. MEASUREMENTS AND RESULTS: All gram-negative pancreatic infections were preceded by intestinal colonization with the same micro-organisms. The risk of developing a pancreatic infection following gram-negative intestinal colonization (15/42 patients) was significantly higher as compared to patients without gram-negative colonization (0/10 patients) (p < 0.001) or to patients in whom E. coli was the only intestinal micro-organism cultured (0/30 patients) (p < 0.001). The occurrence of intestinal E. coli did not increase the risk of pancreatic infection. Gram-negative colonization of the rectum and oropharynx significantly correlated with the later development of pancreatic infection: relative risks 73.7 (p < 0.001) and 13.6 (p < 0.001), respectively. However, when both areas were evaluated simultaneously, the rectum was more significant (p < 0.001). The severity of intestinal intestinal colonization until the moment of pancreatic infection showed an increase in time in all 15 patients. In 11 of 15 patients (73%) these infections occurred within 1 week following the first isolation from the digestive tract. Gram-negative intestinal colonization was associated with a 3.7 fold increased mortality risk (p = 0.004). CONCLUSIONS: Gram-negative intestinal colonization, E. coli excepted, is an early prognostic parameter in patients in whom pancreatic infection has not yet occurred and represents a significantly increased risk of pancreatic infections and mortality.

Actuarial Analysis↗

PubMed1998

The clinical relevance of the Waterlow pressure sore risk scale in the ICU.

OBJECTIVE: To evaluate whether the Waterlow pressure sore risk (PSR) scale has prognostic significance for intensive care patients. DESIGN: A prospective study. SETTING: The surgical intensive care unit (ICU) of the University Hospital Rotterdam. PATIENTS: Data were evaluated from 594 patients who had been admitted to the ICU during the year 1994. METHODS AND RESULTS: Each patient was assessed daily with respect to their Waterlow PSR score and the development of pressure sores in the sacral region. Actuarial statistical methods were used to analyse the predictive value of the risk score. When a patient had a Waterlow PSR score > 25 on admission, the risk of developing a pressure sore was significantly increased compared to patients with a PSR score < 25. After admission, the daily Waterlow PSR scores obtained were significantly associated with the risk of developing a pressure sore. For each additional point this risk increased by 23% (95% confidence interval 17 to 28%). CONCLUSIONS: The Waterlow PSR scale provides the medical and nursing staff at an early stage with reliable information about the risk patients have in developing a pressure sore.

Adolescent↗

PubMed1998

Coated self-expanding metal stents versus latex prostheses for esophagogastric cancer with special reference to prior radiation and chemotherapy: a controlled, prospective study.

BACKGROUND: Self-expanding metal stents seem to be safer than conventional prostheses for palliation of malignant esophagogastric obstruction. However, recurrent dysphagia caused by tumor ingrowth in uncoated types remains a problem. In addition, prior radiation and/or chemotherapy may entail an increased risk of complications. METHODS: Seventy-five patients with an esophagogastric carcinoma were randomly assigned to placement of a latex prosthesis under general anesthesia or a coated, self-expanding metal stent under sedation. At entry, patients were stratified for location of the tumor in the esophagus or cardia and for prior radiation and/or chemotherapy. RESULTS: Technical success and improvement in dysphagia score were similar in both groups. Major complications were more frequent with latex prostheses (47%) than with metal stents (16%) (odds ratio 4.07: 95% CI [1.35, 12.50], p = 0.014). Recurrent dysphagia was not different between latex prostheses (26%) and metal stents (24%). Hospital stay was longer, on average, after placement of latex prostheses than metal stents (6.3 +/- 5.2 versus 4.3 +/- 2.3 days; p = 0.043). Only prior radiation and/or chemotherapy increased the risk of specific device-related complications with respect to the esophagus (12 of 28 [43%] versus 8 of 47 [17%]; odds ratio 3.66: 95% CI [1.24, 10.82], p = 0.029). CONCLUSIONS: Coated, self-expanding metal stents are associated with fewer complications and shorter hospital stay as compared with latex prostheses, and prior radiation and/or chemotherapy increases the risk of device-related complications with respect to the esophagus.

Aged↗

PubMed1998

Morbidity and quality of life in patients with orthotopic and heterotopic continent urinary diversion.

OBJECTIVES: To evaluate morbidity and quality of life (QOL) in patients with continent urinary diversion. METHODS: Morbidity and neobladder function were analyzed in 56 consecutive patients with bladder substitutions. QOL assessment was performed using the Sickness Impact Profile (SIP), supplemented with a detailed voiding and continence questionnaire. RESULTS: Mean age was 44.7 years. Mean follow-up was 41 months. Thirty-one men and 25 women were treated for transitional cell carcinoma (n = 22) or benign conditions (n = 34). In 33 patients, orthotopic (20 Mainz pouch and 13 ileal neobladder) substitutions were performed and in 23, heterotopic substitutions (Indiana pouch) were performed. Early complications required five open reinterventions. Late complications (at more than 3 months) included ureteric stenosis in 5 patients. In 38 patients (68%), full urinary continence was achieved. Spontaneous micturition was possible in 61% of orthotopic substitutions, whereas 15% of patients were required to perform intermittent catheterization only and 24% exhibited a combined voiding pattern. Compared to age-matched reference values, SIP scores showed a negative impact of heterotopic or orthotopic diversion in the SIP categories of emotion, recreation, and social interaction. The latter category included a statement about sexual activity, which was decreased in 50% of patients. In the category of emotion, orthotopic substitutions compared favorably to heterotopic substitutions (P = 0.02). CONCLUSIONS: The morbidity profile is comparable to previous reports. QOL assessment using the SIP revealed a minor advantage for an orthotopic placement which was due to a relatively small number of patients. Most importantly, QOL was found to be favorable for both types of bladder substitute placement.

Adolescent↗

PubMed1998

Ursodeoxycholic acid therapy for primary sclerosing cholangitis: results of a 2-year randomized controlled trial to evaluate single versus multiple daily doses.

BACKGROUND/AIMS: Ursodeoxycholic acid has been reported to be of potential benefit for primary sclerosing cholangitis but little is known about the long-term biochemical, histological and radiological efficacy or the optimum frequency of ursodeoxycholic acid administration. METHODS: A 2-year multicentre randomised controlled trial was initiated to assess the effects of ursodeoxycholic acid (10 mg kg(-1).d(-1), given in either single or multiple daily doses, on symptoms, serum liver tests, cholangiographic and histological findings and the occurrence of treatment failure. Liver biopsies were taken and endoscopic retrograde cholangiography was performed at entry and after 2 years; follow-up examinations were at 3-month intervals. Treatment failure was defined as death, liver transplantation, 4-fold increase in serum bilirubin, variceal bleeding, de novo ascites or cholangitis. Actuarial survival was compared with predicted survival using the revised Mayo natural history model for primary sclerosing cholangitis. RESULTS: Forty-eight patients were enrolled. In one case, ursodeoxycholic acid had to be discontinued because of gastro-intestinal complaints. No other side-effects were observed. After 2 years of follow-up, treatment was not associated with a beneficial effect on either symptoms or liver histology. Serum liver tests (alkaline phosphatase, y-glutamyl transferase, aspartate aminotransferase) improved significantly in both groups, while serum bilirubin (which was near normal at entry) and IgG remained stable. No major changes in radiographic bile duct appearance seemed to be present. After 2 years, actuarial survival was 91% (95 CI 83%-99%), which is comparable to the predicted 97% survival rate. Treatment failure occurred in 15% of cases. No significant differences in any of the study endpoints (symptoms, serum liver tests, cholangiographic findings, histology, disease progression) were found between the two groups. CONCLUSIONS: Ursodeoxycholic acid is well tolerated in primary sclerosing cholangitis. Significant effects on biochemical parameters were found and symptoms, bilirubin and histology did not deteriorate. No advantage of a multiple daily dose over a single dose was observed.

Adult↗

PubMed1998

Triple therapy with ursodeoxycholic acid, prednisone and azathioprine in primary biliary cirrhosis: a 1-year randomized, placebo-controlled study.

BACKGROUND/AIMS: Treatment with ursodeoxycholic acid has been shown to decrease the rate of disease progression in patients with primary biliary cirrhosis, although the effect is modest. Since primary biliary cirrhosis has many features of an autoimmune disorder, immunosuppressives added to ursodeoxycholic acid may be of value in the treatment of primary biliary cirrhosis. METHODS: A 1-year randomized, double-blind, placebo-controlled trial was carried out in 50 patients with primary biliary cirrhosis, who had already been treated with ursodeoxycholic acid for at least 1 year, but had not achieved complete disease remission. Patients were randomized to additional prednisone (30 mg per day initially, tapered to 10 mg daily after 8 weeks) and azathioprine (50 mg daily) or placebo. A subgroup of patients received cyclical etidronate and calcium. The principal aim of the study was to assess the short-term benefits and risks of the combined bile acid and low-dose immunosuppressive regimen. Primary endpoints were effects on symptoms, liver biochemistry, liver histology, bone mass and the occurrence of adverse events. RESULTS: Pruritus (p=0.02), alkaline phosphatase, aspartate aminotransferase, IgM and procollagen-III-propeptide improved significantly (all p<0.002) in the combined treatment group as compared to the placebo group. Histological scores for disease activity and disease stage decreased significantly within the combination treatment group (p<0.001). CONCLUSIONS: In patients with primary biliary cirrhosis receiving ursodeoxycholic acid, there is an additional beneficial effect of 1-year treatment with prednisone and azathioprine on symptoms and biochemical, fibrogenetic and histological parameters. These results strongly encourage the evaluation of this triple treatment regimen in long-term controlled trials of adequate size to document its effect on clinical events.

Adult↗

PubMed1998

Infections and bacteriological data after laparoscopic and open gallbladder surgery.

In two hospitals 637 patients undergoing cholecystectomy between June 1989 and June 1993 were entered into a prospective audit. The aim of this study was to determine the incidence of postoperative infections, especially wound infections, after open and laparoscopic biliary surgery and to assess the bacteriological data on these patients. The incidence of minor wound infection was 10.4% (66/637), of major wound infection 3.6% (23/637) and the overall incidence was 14% (89/637). The incidence of wound infection after laparoscopic cholecystectomy was 5.3% (10/189) and all were minor. Significant specific risk factors for developing a wound infection after laparoscopic cholecystectomy were emergency of the operation (P = 0.046) and acute cholecystitis (P = 0.014). Overall, bile cultures were positive in 22%. There were 85 patients (13.3%) with positive bile from the gallbladder. From the laparoscopically operated patients 2.8% had a positive bile culture. The predominant micro-organisms from gallbladder bile were Escherichia coli (56 isolates), Klebsiella spp. (20 isolates) and Streptococcus spp. (16 isolates). There was no relationship between positive gallbladder cultures and wound infection. The consequences of wound infections can be serious and this study showed a morbidity rate comparable with the literature. The incisions used in laparoscopic gallbladder surgery are less susceptible to major problems. This combined with the significantly lower incidence of wound infections after laparoscopic cholecystectomy suggests that routine antibiotic prophylaxis as recommended for biliary surgery in general is now questionable.

Adult↗

PubMed1998

Umbilical artery waveform analysis based on maximum, mean and mode velocity in early human pregnancy.

The objective of this study was to identify the best method for reconstructing blood-flow velocities from the early human umbilical artery to determine the physiological changes in fetal blood-flow velocity and heart rate. Pulsed Doppler recordings from the umbilical artery with a duration of approximately 7 s were made at 10-20 weeks of gestation. For reconstruction of the blood-flow velocity from the Doppler audio signal, the maximum (envelope), mean and mode frequency reconstruction methods were used. For the assessment of variability in blood-flow velocity and heart rate in the umbilical artery, the maximum velocity reconstruction method is preferred because it is relatively insensitive to noise, nonuniform insonation, and wall filter settings.

Adolescent↗

PubMed1998

Vein graft surveillance: is graft revision without angiography justified and what criteria should be used?

PURPOSE: The objective of this study was to assess the accuracy of color-flow duplex surveillance parameters to detect infrainguinal vein graft stenoses and to investigate whether graft revision without angiography is justified. METHODS: In a prospective study in which three centers participated, the data of graft surveillance in 300 patients were analyzed. For the evaluation of surveillance criteria all patients underwent a digital subtraction angiography if a graft stenosis was suspected. To create a control group, in patients with normal grafts a consented digital subtraction angiography was performed also. From these data the accuracy of seven duplex and three ankle blood pressure-derived variables was assessed. The relation between various surveillance criteria and continued graft patency was determined with life table analysis with the transient state method. RESULTS: The mean follow-up period was 20 months (range, 1 to 40 months). At univariate and multivariate analysis the peak systolic velocity (PSV) ratio provided the best correlation with angiographic stenoses > or = 70% (PSV ratio cutoff 3.0: sensitivity 80%, specificity 84%). This finding did not differ between the participating centers. With life table methods it was demonstrated that the best combination of efficacy (limitation of the number of unnecessary revisions), safety (minimal number of correctable lesions missed), and reduction of angiograms was obtained by a two-parameter surveillance algorithm. This algorithm included a PSV ratio < 2.5 to delineate patients in whom a conservative approach without angiography or revision was appropriate, a PSV ratio > or = 4.0 to indicate patients in whom vein graft revision without angiography could be scheduled, and a group with PSV ratios between 2.5 and 4.0 in whom angiography was to be performed to determine clinical management on the basis of the stenosis severity. This algorithm had a positive predictive value of 93% and a negative predictive value of 89%. In addition, it resulted in a reduction of the number of angiograms of 49% compared with a policy of angiographies in all patients with a PSV ratio > or = 2.5. CONCLUSIONS: The best criterion to identify a failing graft is the PSV ratio. With a two-parameter algorithm for vein graft surveillance, the incidence of unnecessary revisions and of missed high-grade lesions was acceptably low, whereas the number of angiograms was reduced by one half.

Adult↗

PubMed1998

Economising vein-graft surveillance programs.

OBJECTIVES: To investigate the effectiveness of two alternative vein-graft surveillance strategies. In the first strategy surveillance was restricted to patients with a possible higher risk of significant stenosis development, i.e., those with a moderate stenosis identified early after the operation. In the second strategy the effects of reducing the number of duplex tests per patient was examined. PATIENTS AND METHODS: In a prospective study in three vascular surgical departments 300 patients (300 femoropopliteal or distal grafts) underwent duplex surveillance during the first year after the operation. The duplex-derived PSV-ratio was considered to represent the degree of stenosis. Arteriographic confirmation of suspected stenoses was routinely obtained, and patients without a suspected graft stenosis underwent a consented arteriogram during the first postoperative year. The decision to perform a graft revision was taken on the basis of an arteriographic stenosis of at least 70% diameter reduction. In the first strategy graft categories were defined on the basis of the first postoperative duplex examination: grafts with a PSV-ratio < 1.5, grafts with a PSV-ratio < 1.5-2.0, grafts with a PSV-ratio of 2.0-2.5, grafts with PSV-ratios 2.5-3.0, and grafts with PSV-ratios > 3.0. The primary patency rate at 12 months was compared for these categories. In the second alternative strategy the number of examinations and the percentage of event causing de novo stenoses were analysed per surveillance interval. RESULTS: The presence of moderate abnormalities at the initial duplex scan did not identify patients with a high risk of an event, as initial PSV-ratios of 1.5-2.0 and 2.0-2.5 (early mild-moderate lesions) had comparable 12-month primary patencies to patients with a PSV-ratio < 1.5 (completely normal grafts): (63%, 73%, and 71%, respectively). The interval incidence of event causing de novo stenoses was 8% of the total number of duplex tests performed at 3 months, and 8% at 6 months after the operation. In patients who had no previous intervention for stenosis and had a normal bypass during the first 6 months postoperatively, a sharp drop in this incidence was seen at 9 and 12 months, with event causing de novo stenoses observed in only 2% and 1% of all duplex tests. CONCLUSIONS: All patients should be included in a surveillance program, as the presence of a normal vein graft at the first duplex examination does not rule out the subsequent development of graft stenosis. The duration of the surveillance period may be restricted to the first 6 months after operation in patients who have a normal bypass during that time period, as only few stenoses will be missed by this policy.

Adult↗

PubMed1998

Heart rate and flow velocity variability as determined from umbilical Doppler velocimetry at 10-20 weeks of gestation.

1. The aim of this study was to define from umbilical artery flow velocity waveforms absolute peak systolic and time-averaged velocity, fetal heart rate, fetal heart rate variability and flow velocity variability, and the relation between fetal heart rate and velocity variables in early pregnancy.2.A total of 108 women presenting with a normal pregnancy from 10 to 20 weeks of gestation consented to participate in a cross-sectional study design. Doppler ultrasound recordings were made from the free-floating loop of the umbilical cord.3. Umbilical artery peak systolic and time-averaged velocity increased at 10-20 weeks, whereas fetal heart rate decreased at 10-15 weeks of gestation and plateaued thereafter. Umbilical artery peak systolic velocity variability and fetal heart rate variability increased at 10-20 and 15-20 weeks respectively.4. The inverse relationship between umbilical artery flow velocity and fetal heart rate at 10-15 weeks of gestation suggests that the Frank-Starling mechanism regulates cardiovascular control as early as the late first and early second trimesters of pregnancy. A different underlying mechanism is suggested for the observed variability profiles in heart rate and umbilical artery peak systolic velocity. It is speculated that heart rate variability is mediated by maturation of the parasympathetic nervous system, whereas peak systolic velocity variability reflects the activation of a haemodynamic feedback mechanism.

Blood Flow Velocity↗

PubMed1998

A randomized trial in primary biliary cirrhosis comparing ursodeoxycholic acid in daily doses of either 10 mg/kg or 20 mg/kg. Dutch Multicentre PBC Study Group.

BACKGROUND: Ursodeoxycholic acid (UDCA) prolongs transplantation-free survival in primary biliary cirrhosis (PBC). However, the optimal therapeutic dose has not been established. AIM: To compare the effects of UDCA administered in daily doses of 10 vs. 20 mg/kg on symptoms, liver biochemistry and biliary UDCA enrichment. METHODS: A 6-month multicentre randomized open controlled trial was conducted to assess the effects of an increase in the dose of UDCA to 20 mg/kg/day vs. continuation of 10 mg/kg/day for patients who had not achieved biochemical normalization during treatment for at least 6 months with the 10 mg/kg dose. Clinical and laboratory evaluations were performed at entry and at 3-month intervals. The percentage UDCA in duodenal bile was assessed at entry and at 6 months. RESULTS: Sixty-one patients were enrolled. No side-effects of UDCA were observed. Within the 20 mg/kg/day group significant decreases were found for alkaline phosphatase (- 8%; P = 0.003), aspartate aminotransferase (- 11%; P = 0.01), alanine aminotransferase (- 17%; P < 0.001), gamma-glutamyl transferase (- 34%; P < 0.001), immunoglobulin M (- 11%; P = 0.002) and cholesterol (- 8.1%; P < 0.001). In the 10 mg/kg group none of these parameters differed significantly from baseline. No significant differences between dose groups for symptom scores or serum bilirubin were found. Biliary enrichment with UDCA increased from 37% to 46% in the 20 mg/kg group (P = 0.02) while remaining stable in the 10 mg/kg group. CONCLUSIONS: Liver biochemistry improved in PBC patients receiving UDCA 20 mg/kg/day compared to a dose of 10 mg/kg/day. Both doses were equally well tolerated. These results indicate that UDCA 10 mg/kg/ day is a suboptimal dose for treating PBC.

Adult↗