Estimated radiation risk of cancer from medical imaging in haemodialysis patients.

BACKGROUND: In recent years the widespread use of medical procedures increased the cumulative effective doses of ionizing radiation. Although many haemodialysis patients undergo multiple examinations with high radiation exposure, no data are available characterizing their attendant potential risks of cancer. METHODS: The radiation exposures were obtained from a retrospective study of 159 consecutive haemodialysis patients with a follow-up duration ≥ 1 year. Effective dose and organ dose were estimated on an individual basis. Radiation risk was expressed as risk of exposure-induced death (REID) (%). RESULTS: The 159 patients (101 males) were followed for a median of 2.7 years (mean 3.0 years). A total of 486 patient-years were available for follow-up. The mean age at study entry was 65.3 years. The mean cumulative organ doses were 103, 102, 100, 99, 77 and 58 mSv for kidneys, lung, stomach, liver, colon and bone marrow, respectively. On average, computed tomography, nuclear medicine and interventional radiology accounted for 90, 4.5 and 5.5% of organ doses, respectively. The average REID was 0.99% (i.e. odds 1 in 100) and the median REID was 0.45%. At univariate analysis, increasing age and presence of diabetes were independent predictors of lower REID, whilst patients eligible for kidney transplantation were exposed to a significantly higher REID. At multivariate analysis, younger age was an independent predictor of higher REID. CONCLUSIONS: The excess cancer risk-attributable radiation exposure in haemodialysis patients is not negligible. Particular attention should be paid to younger patients and to patients who will undergo kidney transplantation.

Cumulative radiation dose from medical imaging in kidney transplant patients.

BACKGROUND: Although many patients undergoing kidney transplant are exposed to multiple examinations that increase cumulative effective doses (CEDs) of ionizing radiation, no data are available characterizing their total longitudinal radiation burden and relating radiation burden with risk factors for more exposure. METHODS: We did a retrospective cohort study of 92 patients (mean age 52 years; range: 20-75 years) who underwent kidney transplant at University Hospital, Novara, Italy, that evaluated all following medical imaging procedures involving ionizing radiation undergone beginning June 2007, and all subsequent procedures through August 2011, at the centre. RESULTS: The mean and median annual CED were 17.2 and 4.9 millisieverts (mSv) per patient-year. The mean and median total CED per patient over the study period were 46.1 and 17.3 mSv, respectively. Twenty-eight and 12% of patients had total CED >50 and 100 mSv, values which are associated with a good or strong evidence of an increased cancer mortality risk, respectively. Computed tomography scanning accounted for 73% of the total CED. The annual CED was significantly higher in incident patients and in patients with ischaemic heart disease and cancer. CONCLUSION: In this institution, multiple testing of kidney transplant patients was common in many patients associated with high cumulative estimated doses of ionizing radiation.

Estimated radiation exposure from medical imaging in hemodialysis patients.

Radiation exposure accompanying medical imaging associates with cancer risk. Patients with recurrent or chronic diseases may be especially at risk, because they may undergo more of these procedures. The aim of this study was to assess the individual cumulative effective doses (CEDs), which quantify radiation from medical imaging procedures, in a cohort of 106 hemodialysis patients during a median follow-up of 3 years. We retrospectively calculated individual radiation exposures by collecting the number and type of radiologic procedures from hospital records. We also estimated organ doses for computed tomography procedures. The mean and median annual CEDs were 21.9 and 11.7 mSv per patient-year, respectively. The mean and median total CEDs per patient during the study period were 57.7 and 27.3 mSv, respectively. By radiation dose group, we classified 22 patients as low (<3 mSv/yr), 51 as moderate (3 to <20 mSv/yr), 22 as high (20 to <50 mSv/yr), and 11 as very high (≥50 mSv/yr). Seventeen patients had a total CED >100 mSv, a value associated with a substantial increase in risk for cancer-related mortality. Of the total CED,s 76% was a result of CT scanning. The annual CED significantly associated with age and transplant waitlist status. In summary, this study shows that a significant fraction of surviving hemodialysis patients during a 3-year period receives estimated radiation doses that may put them at an increased risk for cancer.

[Human papillomavirus infection and cervical intraepithelial neoplasia in dialyzed patients]. / Infezione da papilloma virus e neoplasia intraepiteliale cervicale in pazienti dializzate: esperienza monocentrica.

Human papillomavirus (HPV) infection is a risk factor for the development of cervical intraepithelial neoplasia (CIN). The incidence of certain cancers such as HPV-associated CIN is higher among dialysis patients than in the general population. In the literature there are few studies on the prevalence of HPV infection among dialyzed women and almost all of these studies concerned women with positive Pap smears. We enrolled 73 hemodialyzed women attending our center from January 2009 to December 2010; 29 denied informed consent and 44 underwent Pap tests and cervical curettage for HPV (mean age 62 ± 15 years). We found HPV positivity in 6 women (prevalence 13.6%). The prevalence of CIN in our sample was also 13.6% (6/44), 83.3% of which HPV related. Since cervical curettage for HPV is a cheap and easy to perform test with high specificity and sensitivity, we believe it is worthwhile including it in the pre-transplant workup of such women to lower the incidence of CIN in dialyzed patients and transplant recipients.

[Native vascular access for hemodialysis in patients with diabetes: a single-center experience]. / L'accesso vascolare per dialisi su vasi nativi nel paziente diabetico: esperienza di un singolo centro.

With 135 million cases the prevalence of diabetes mellitus (DM) is very high worldwide. Diabetic nephropathy is a major complication of DM. In many countries diabetic nephropathy has become the most frequent cause of endstage renal disease. It is believed that in diabetic patients the creation of a native vascular access (NVA) might be difficult. We evaluated 274 occurrences of NVA creation during the period January 2003 to December 2008: 68 in diabetic patients (group 1) and 206 in nondiabetics (group 2). We compared the type of NVA, primary failure, and primary patency in these groups. Age was significantly higher in diabetic patients (68 vs 64 years; p < 0.05). No statistical differences in primary failure between groups were found for any NAV. Wrist vascular access survival rates were higher in diabetic versus nondiabetic patients (56.9% vs 20.7% at 72 months). No statistical differences were observed between groups in primary patency rates for middle- and upper-arm vascular access. According to our experience diabetes does not lead to additional difficulties in the creation of permanent vascular access, provided proper physical and instrumental examination is performed. Despite the advanced age of the diabetic patients in our study, wrist vascular access showed better results in this group than in nondiabetic patients on long-term follow-up.

Stenotrophomonas maltophilia: an emerging pathogen in dialysis units.

Infection is an important cause of morbidity and mortality among patients with end stage renal disease. Stenotrophomonas maltophilia is an unusual yet emerging pathogen in dialysis units. We performed a systematic PubMed/Medline and Scopus review of peer-reviewed English papers on S. maltophilia infections among patients undergoing chronic dialysis, with regard to vascular accesses, systemic infections and environment contaminations. Moreover, we suggest a treatment algorithm to preserve the patient and the permanent dialysis catheters.

Report of a transient increase in tunneled catheter infections following dialysis facility transfer to a prefabricated structure.

PURPOSE: Despite the efforts to promote the native artero-venous fistula as dialysis access, the use of tunneled central venous catheters (tCVC) is increasing. Main complications remain infections of the access, and the environment plays an important role in determining them; however, no studies are available that report dialysis provided in prefabricated temporary buildings. The aim of our study was to assess the incidence of tCVC infections in a container building. METHODS: Since May 2009 our Dialysis Center has been located in a container building. The occurrence of local and systemic infections of tCVC when dialysis was provided in the container was compared with the previous two years, when dialysis was provided at the "Home" center. Each year was also divided into semesters to maintain the temporary relationship between the new location and the infections. RESULTS: tCVCs represented approximately 13% of all vascular accesses. In the first six months in the temporary building, 50% of patients presented infections, compared to 13% to 20% during the other periods (P=0.02). In the first six months in the container the incidence of infections was 1.44 per 1000 catheters-days, higher than in any other semester (P=0.02). More infections requiring systemic antibacterial agents occurred over this period. CONCLUSIONS: Our study demonstrates that, when a dialysis center is moved to a prefabricated temporary building, the likelihood of tCVC infections increases within the initial months and returns back to the previous levels after a period of adaptation.

Leclercia adecarboxylata and catheter-related bacteraemia: review of the literature and outcome with regard to catheters and patients.

Infection is a common complication in patients carrying a central venous catheter (CVC) and is associated with increased morbidity and mortality. Leclercia adecarboxylata is an unusual but emerging pathogen in healthy and immunocompromised patients. We report a case of L. adecarboxylata bacteraemia in a patient with a haemodialysis tunnelled CVC. In accordance with the susceptibility to the tested antimicrobials, a long-course treatment with intravenous gentamicin plus amoxicillin-clavulanic acid and gentamicin-lock therapy was adopted. The patient had a full recovery and the catheter was not removed. We also performed a systematic PubMed/Medline and Scopus review of peer-reviewed English papers on L. adecarboxylata infections, focusing on bacteraemia in patients with different types of CVCs. Moreover, we suggest a treatment algorithm to preserve the patient and maintain the CVC.

The middle arm arteriovenous fistula is an additional option to expand autogenous hemodialysis access.

PURPOSE: The native arteriovenous fistula is the gold standard for hemodialysis access. Unfortunately, the wrist fistula is often not practical and the upper arm fistula is hindered by several complications. The aim of this study is to assess the safety of the middle-arm fistula as additional native access. METHODS: We reviewed and compared the patency rates at 12, 48, and 60 months of distal, middle, and upper arm fistula performed from January 2003 to December 2008. For diabetic and old patients we compared distal and middle-arm fistulas. RESULTS: Of 273 native access, 149 (54.6%) were distal, 92 (33.7%) middle-arm, and 32 (11.7%) upper fistula. Patency rates were 81%, 58%, and 52% for distal, 85%, 69%, and 69% for middle-arm, and 82%, 46%, and 29% for upper arm fistula (P NS). Patency rates were 92%, 70%, and 54% in middle-arm fistula as first access and 80%, 71%, and 71% in middle-arm fistula as a rescue access (P NS). Among patients > 75 years patency rates were 78%, 62%, and 62% for distal and 87%, 67%, and 67% for middle-arm fistula. Among diabetic subjects patency rates were 81%, 58%, and 58% for middle-arm and 65%, 57%, and 57% for distal fistula at 12, 48, and 60 months (P NS) respectively. CONCLUSIONS: A middle-arm fistula is as safe as a distal fistula among dialyzed patients, even diabetic and elderly. This could be considered a reliable option to expand native accesses.

Plasma B-type natriuretic peptide in dialyzed patients: marker of cardiovascular disease or link to plasma refilling.

BACKGROUND: B-type natriuretic peptide (BNP) is released in response to extracellular volume and blood pressure (BP) overload and is a risk factor for cardiovascular diseases (CVD). BNP is increased in dialyzed patients (HDpts). The aim of this study was to evaluate the relationships between BNP and renin, aldosterone and blood volume reduction rate (BV/WL), with the presence of CVD and mortality. METHODS: Fifty-one HDpts aged 70 ± 14 years were enrolled. BP, BV/WL, BNP, aldosterone, renin, C-reactive protein (CRP), troponin I and routine biochemistry were measured. According to the predialytic plasma BNP levels, the patients were divided into group A with higher BNP and group B with lower BNP than the median value of 330 pg/mL. Follow-up was 1 year. RESULTS: After HD, plasma BNP (449.6 ± 582.2 pg/mL vs. 264.1 ± 269.8 pg/mL, p=0.0008) and aldosterone (421.8 ± 573.4 pg/mL vs. 265.1 ± 566.2 pg/mL, p=0.0003) decreased, but not rennin. BNP decreased more after hemodiafiltration than after standard HD (-55.1% ± 28.5% vs. -26.5% ± 19.5%, p=0.002). Patients in group A exhibited more diabetes (58% vs. 28%, p=0.03), ischemic heart disease (42% vs. 16%, p=0.04), left ventricular hypertrophy (88.8% vs. 33.3%, p<0.001), elevated levels of troponin I, CRP (50% vs. 24%, p=0.05), and low BV/BWL in a lower percentage (8% vs. 32%, p=0.03). After 11.2 ± 3.5 months, 8 patients (33.3%) had died in group A and 2 (8%) in group B (p=0.02). CONCLUSION: This study demonstrates that BNP is high in HDpts and decreases after HD. It is correlated with a good capacity for plasma refilling, with diabetes, CVD and short-term mortality risk.