Israel Medical Association Journal

The increasing use of computerized medical records has made the clinical data of the entire population available for epidemiological research. The resultant accessibility to this information mandates careful adaptions of ethical guidelines regarding the handling of clinical data. At the same time it grants a unique opportunity to explore the clinical nature of health and disease in large populations across all of society’s strata, socioeconomic levels, ethnicities, and geographic locations regardless of their vicinity or distance to tertiary care centers. Analysis of large databases allows us to learn the public‘s behavior towards medical services and to investigate how medical interventions affect outcomes over time. Moreover, interaction between different co-morbidities can also be better understood by large population studies. The huge numbers of patients involved in these studies provide a good model of multivariate analysis, a statistical tool that by following proper population adjustments underlines the true independent associations between different conditions. Nevertheless, the limitations of these studies should be borne in mind, such as in-built imprecision of diagnoses, incompleteness of the medical data, and the fact that these databases were initially planned for clinical and not investigational use. 

Background: Various vena cava filters (VCF) are designed with the ability to be retrieved percutaneously. Yet, despite this option most of them remain in the inferior vena cava (IVC). 

Objectives: To report our experience in the placement and retrieval of three different types of VCFs, and to compare the indications for their insertion and retrieval as reported in the literature.

Methods: During a 5 year period three types of retrievable VCF (ALN, OptEase, and Celect) were inserted in 306 patients at the Rabin Medical Center (Beilinson and Hasharon hospitals). Indications, retrieval rates, median time to retrieval, success and complications rate were viewed and assessed in the three groups of filter types and were compared with the data of similar studies in the literature.

Results: Of the 306 VCFs inserted, 31 (10.1%) were retrieved with equal distribution in the three groups. In most patients the reason for filter insertion was venous thromboembolic events (VTE) and contraindications to anticoagulant therapy. Mean age was 68.38 ± 17.5 years (range 18–99) and was noted to be significantly higher compared to similar studies (53–56 years) (P < 0.0001). Multi-trauma patients were significantly older (71.11 ± 14.99 years) than post-pulmonary embolism patients (48.03 ± 20.98 years, P < 0.0001) and patients with preventive indication (26.00 ± 11.31, P < 0.0001). The mean indwelling time was 100.6 ± 103.399 days. Our results are comparable with the results of other studies, and there was no difference in percentage of retrieval or complications between patients in each of the three groups. 

Conclusions: In 1 of 10 patients filters should be removed after an average of 3.5 months. All three IVC filter types used are safe to insert and retrieve.

 

Background: Recent studies show that vaccination of health care workers (HCW) might reduce influenza transmission and mortality among hospitalized patients. No studies have compared the incidence of laboratory-proven influenza in vaccinated versus unvaccinated hospital HCW. 

Objectives: To evaluate the effectiveness of influenza vaccination among hospital HCW and to examine the attitudes of this population towards influenza vaccination.

Methods: We performed a prospective cohort study between 1 January and 30 April 2014 of 1641 HCW at our medical center; 733 were vaccinated and 908 not vaccinated. A random sample of 199 subjects was obtained: 97 vaccinated and 102 non-vaccinated. Participating individuals were contacted on a weekly basis during the flu season and were asked to report any respiratory or flu symptoms and, if positive, to undergo a polymerase chain reaction (PCR) test for influenza. 

Results: In the general HCW population, vaccination was more frequent among physicians 298/498 (58%) than among nurses (324/862 (38%) and among males than females. Flu symptoms were reported by 20 of 199 participants, 13 in the non-vaccinated group (12.7%) and 7 in the vaccinated group (7.2%). A positive PCR test for influenza A virus was present in 4 of 20 people tested (20%). All positive cases were from the non-vaccinated group (P = 0.0953). 

Conclusions: Non-vaccinated HCW showed a higher, although not statistically significant, tendency for contracting laboratory-proven influenza than the vaccinated population. The main reasons for vaccination and non-vaccination were personal beliefs and habits. Education efforts are needed to improve compliance. Larger studies could further clarify this issue.

 

Background: Transvenous lead extraction can lead to tricuspid valve damage. 

Objectives: To assess the incidence, risk factors and clinical outcome of tricuspid regurgitation (TR) following lead extraction.

Methods: We prospectively collected data on patients who underwent lead extraction at the Sheba Medical Center prior to laser use (i.e., before 2012). Echocardiography results before and following the procedure were used to confirm TR worsening, defined as an echocardiographic increase of at least one TR grade. Various clinical and echocardiographic parameters were analyzed as risk factors for TR. Clinical and echocardiographic follow-up was conducted to assess the clinical significance outcome of extraction-induced TR.

Results: Of 152 patients who underwent lead extraction without laser before 2012, 86 (56%) (192 electrodes) had echocardiography results before and within one week following the procedure. New or worsening TR was discovered in 13 patients (15%). Use of mechanical tools and younger age at extraction were found on multivariate analysis to be factors for TR development (P = 0.04 and P = 0.03 respectively). Average follow-up was 22.25 ± 21.34 months (range 8–93). There were no significant differences in the incidence of right-sided heart failure (50% vs. 23%, P = 0.192) or hospitalizations due to heart failure exacerbations (37.5% vs. 11%, P = 0.110). No patient required tricuspid valve repair or replacement. Death rates were similar in the TR and non-TR groups (20% vs. 33%).

Conclusions: TR following lead extraction is not uncommon but does not seem to affect survival or outcomes such as need for valve surgery. Its long-term effects remain to be determined. 

 

Background: Selection of appropriate reference charts for fetal biometry is mandatory to ensure an accurate diagnosis. Most hospitals and clinics in Israel use growth curves from the United States. Charts developed in different populations do not perform well in the Israeli population.

Objectives: To construct new reference charts for fetal biparietal diameter (BPD), head circumference (HC), abdominal circumference (AC) and femur length (FL), using a large sample of fetuses examined at 14–42 weeks gestational age in a medical center and a community ultrasound unit located in two different regions of Israel. 

Methods: Data from the medical center and the community clinic were pooled. The mean and standard error of each measure for each week was calculated. Based on these, reference charts were calculated using quantiles of the normal distribution. The performance of the reference charts was assessed by comparing the new values to empirical quantiles.

Results: Biometric measurements were obtained for 79,328 fetuses. Growth charts were established based on these measurements. The overall performance of the curves was very good, with only a few exceptions among the higher quantiles in the third trimester in the medical center subsample.

Conclusions: We present new local reference charts for fetal biometry, derived from a large and minimally selected Israeli population. We suggest using these new charts in routine daily obstetric practice.

 

Background: It has been suggested that sleep disordered breathing (SDB) during pregnancy may adversely influence maternal as well as fetal well being.

Objectives: To examine the effect of maternal SDB on neonatal neurological examination and perinatal complications.

Methods: Pregnant women of singleton uncomplicated pregnancies were prospectively recruited from a community and hospital low risk obstetric surveillance. All participants completed a sleep questionnaire in the second trimester and underwent ambulatory sleep evaluation (WatchPAT, Itamar Medical, Caesarea, Israel). They were categorized as SDB (apnea hypopnea index > 5) and non-SDB. Maternal and newborn records were reviewed and a neonatal neurologic examination was conducted during the first 48 hours. 

Results: The study group included 44 women and full-term infants; 11 of the women (25%) had SDB. Mean maternal age of the SDB and non-SDB groups was 32.3 ± 2.8 and 32.5 ± 4.7 years, respectively (P = 0.86). Mean body mass index before the pregnancy in the SDB and non-SDB groups was 25.8 ± 4.7 and 22.0 ± 2.5 kg/m2, respectively (P = 0.028). No differences were found between infants born to mothers with SDB and non-SDB in birth weight (3353.8 ± 284.8 vs. 3379.1 ± 492.4 g), gestational age (39.5 ± 0.9 vs. 39.2 ± 1.5 weeks), 5 minute Apgar scores (9.8 ± 0.6 vs. 9.9 ± 0.3), and neurologic examination scores (95.2 ± 3.9 vs. 94.6 ± 4.1). P value for all was not significant. 

Conclusions: Our preliminary results suggest that maternal mild SDB during pregnancy has no adverse effect on neonatal neurologic examination or on perinatal complications. 

 

Background: In the last decade the number of robotic devices and the medical procedures utilizing them increased significantly around the world.

Objective: To evaluate the implementation of robotic surgeries in Israel in various surgical disciplines.

Methods: We conducted a retrospective study accessing information about the annual purchases of robots, the number of physicians trained for their use, and the number of robotic surgeries performed each year, according to indications of surgery and the disciplines of the operating medical staff. The data were taken from the database of Intuitive Surgical Inc.

Results: Six robots were purchased by six medical centers in Israel during the years 2008–2013. There are currently 150 physicians trained to use the robot in one of the simulators of Intuitive Surgical Inc. Of them, 104 are listed as active robotic surgeons. Most of these physicians are urologists, gynecologists, or general surgeons. The number of robotic surgeries increased each year in all fields in which it was implemented. In 2013, 975 robotic surgeries were performed in Israel. Of them, 52% were performed by urologists; 80% of which were radical prostatectomy. 

Conclusions: The use of robotic surgery increased considerably in Israel over recent years, in urology, gynecology, general surgery, and otolaryngology. Despite the lack of conclusive evidence of the advantages of robotic surgery over the laparoscopic approach, the market power and the desire to be at the technological forefront drive many medical centers to purchase the robot and to train physicians in its use.

 

Background: Several studies have identified associations between low vitamin D concentrations and risk of upper respiratory infections (URI). T lymphocytes have a major anti-viral role, are affected by vitamin D metabolism, and may mediate the link between vitamin D and URIs. Competitive swimmers have a relatively high rate of URIs, alongside a high prevalence of low vitamin D concentration. 

Objectives: To examine the associations linking T cell receptor excision circles (TREC, markers of thymus activity), circulating 25(OH)D concentrations and the effect of vitamin D supplementation, and URI symptoms in young competitive swimmers.

Methods: We tested 82 adolescent swimmers for serum 25(OH)D and TREC concentrations and found that 55 had vitamin D insufficiency. Randomized supplementation of either vitamin D3 or placebo was given for 12 winter weeks. URI symptoms were recorded weekly. The associations between TREC copy numbers, vitamin D and URI burden were examined.

Results: TREC concentrations decreased with the participants’ age (r = -0.346, P = 0.003), with no significant between-gender difference. TREC concentrations did not materially differ among subjects with normal, insufficient or deficient vitamin D status, and were not affected by vitamin D supplementation. No significant correlations were found between TREC levels or their changes during the study period, and mean URI severity or duration. 

Conclusions: Thymus activity, represented by higher TREC levels, was not related to vitamin D concentrations or status, and was not affected by vitamin D supplementation in adolescent swimmers. TREC concentrations were not associated with URI severity or duration in this population.

 

Background: Stroke is a leading cause of death and disability worldwide. The risk factors for stroke overlap those for cardiovascular disease. Atrial fibrillation (AF) is a particularly strong risk factor and is common, particularly in the elderly. Maccabi Healthcare Services (MHS) has maintained a vascular registry of clinical information for over 100,000 members, among them patients with heart disease and stroke. 

Objectives: To determine the prevalence of stroke in MHS, and whether the association of AF and stroke, along with other risk factors, in the Maccabi population is similar to that in published studies.

Methods: Data on stroke and AF patients aged 45 and older were collected from the database for the year 2010, including age, previous transient ischemic attack (TIA), body mass index (BMI), prior myocardial infarction (MI), diabetes, hypertension, anticoagulation and dyslipidemia. A cross-sectional analysis was used to estimate stroke prevalence by AF status. A case-control analysis was also performed comparing a sample of stroke and non-stroke patients. This permitted estimation of the strength of associations for atrial fibrillation and various other combinations of risk factors with stroke. 

Results: Stroke prevalence ranged from 3.5 (females, age 45–54 years) to 74.1 (males, age 85+) per thousand in non-AF members, and from 29 (males, age 45–54) to 165 (males, age 85+) per thousand for patients with AF. AF patients had significantly more strokes than non-AF patients in all age groups. Stroke prevalence increased with age and was significantly higher in males. Multivariable analysis revealed that male gender, increasing age, AF, hypertension, diabetes, and history of TIA were highly significant risk factors for stroke. In addition, for males, dyslipidemia and prior MI were moderately strong risk factors. 

Conclusions: Analysis of the MHS vascular database yielded useful information on stroke prevalence and association of known risk factors with stroke, which is consistent with the epidemiological literature elsewhere. Further analysis of health fund data could potentially provide useful information in the future.