Clinical outcomes of delayed mechanical thrombectomy: Descriptive analysis and development of a screening tool.

BACKGROUND AND PURPOSE: Limited data guide the selection of patients with large vessel occlusion ischaemic stroke who may benefit from referral to a distant tertiary centre for mechanical thrombectomy (MT). We aimed to characterize this population, describe clinical outcomes and develop a screening system to identify patients most likely to benfit from delayed mechanical thrombectomy (MT). METHODS: We undertook a retrospective cohort analysis enrolling patients transferred from regional sites to one of two MT comprehensive stroke units with a time from non-contrast computed tomography (NCCT) of the brain to reperfusion of 4 h or more. We describe Alberta Stroke Programme Early Computed Tomography Score (ASPECTS), National Institute of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) in our patients and compare these patients to those in extended-time-window trials. Lastly, we developed and validated a scoring model to help clinicians identify appropriate patients based on variables associated with poor outcomes. RESULTS: We included 563 patients, 46% of whom received thrombolysis; the median (interquartile range [IQR]) ASPECTS was 8 (7-10) and the median (IQR) NIHSS score was 16 (11-20). The median (IQR) symptom to mechanical reperfusion time was 390 (300-580) min. Eight patients (1%) had a symptomatic haemorrhage. We achieved good clinical outcome (defined as mRS score ≤2) in 299 patients (54%). Age, diabetes, NIHSS score and ASPECTS were used to create a weighted scoring system with a validated area under the curve of 0.83 (95% confidence interval 0.74-0.92). CONCLUSION: Our study shows, in highly selected patients, that delayed MT many hours after baseline NCCT is associated with good clinical outcomes. However, older patients with diabetes, high NIHSS score and low ASPECTS may not benefit from transfer to a hub centre many hours away for MT in this model of care.

Gastroenterology service in a teaching hospital in rural New Zealand, 1991-2003.

AIM: To retrospectively collect inpatient and outpatient data and to assess the use of endoscopic procedures during the years 1991, 1997 and 2003 to analyse for trends. METHODS: This retrospective survey was conducted in a University-associated Gastroenterology Unit offering secondary and tertiary health care services for a population of approximately 182,000 people in Southern New Zealand. Data collected included patient contacts (in- and outpatients), gastroscopic and colonoscopic investigations. RESULTS: We observed a significant increase in the absolute numbers of patient contacts over the years (1991: 2308 vs 1997: 2022 vs 2003: 2783, P < 0.0001) with inflammatory bowel disease, other diseases of the colon, anus and rectum and iron studies related disorders decreasing significantly but liver disease and constipation increasing linearly over time. The use of endoscopy services remained relatively stable but colonoscopic investigations for a positive family history of colorectal cancer increased significantly while more gastroscopies were performed for unexplained anaemia. CONCLUSION: The whole spectrum of gastroenterology contacts was studied. A substantial proportion of colonoscopies and outpatient consultations were undertaken to screen for colorectal cancer. This proportion is likely to grow further. Our findings have implications for the recruitment and training of the next generation of gastroenterologists.

Lithium-induced nephrogenic diabetes insipidus: renal effects of amiloride.

BACKGROUND AND OBJECTIVES: Polyuria, polydipsia, and nephrogenic diabetes insipidus have been associated with use of psychotropic medications, especially lithium. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The impact of psychotropic medications on urinary concentrating ability and urinary aquaporin 2 (AQP2) excretion was investigated after overnight fluid deprivation, and over 6 h after 40 microg of desmopressin (dDAVP), in patients on lithium (n = 45), compared with those on alternate psychotropic medications (n = 42). RESULTS: Those not on lithium demonstrated normal urinary concentrating ability (958 +/- 51 mOsm/kg) and increased urinary excretion of AQP2 (98 +/- 21 fmol/micromol creatinine) and cAMP (410 +/- 15 pmol/micromol creatinine). Participants taking lithium were divided into tertiles according to urinary concentrating ability: normal, >750 mOsm/kg; partial nephrogenic diabetes insipidus (NDI), 750 to 300 mOsm/kg; full NDI, <300 mOsm/kg. Urinary AQP2 concentrations were 70.9 +/- 13.6 fmol/micromol creatinine (normal), 76.5 +/- 10.4 fmol/micromol creatinine (partial NDI), and 27.3 fmol/micromol creatinine (full NDI). Impaired urinary concentrating ability and reduced urinary AQP2, cAMP excretion correlated with duration of lithium therapy. Other psychotropic agents did not impair urinary concentrating ability. Eleven patients on lithium were enrolled in a randomized placebo-controlled crossover trial investigating the actions of amiloride (10 mg daily for 6 wk) on dDAVP-stimulated urinary concentrating ability and AQP2 excretion. Amiloride increased maximal urinary osmolality and AQP2 excretion. CONCLUSIONS: By inference, amiloride-induced reduction of lithium uptake in the principal cells of the collecting duct improves responsiveness to AVP-stimulated translocation of AQP2 to the apical membrane of the principal cells.

Lithium-induced reduction in urinary concentrating ability and urinary aquaporin 2 (AQP2) excretion in healthy volunteers.

BACKGROUND: Lithium therapy is associated with the development of nephrogenic diabetes inspidus. Experimentally, lithium inhibits arginine vasopressin (AVP)-stimulated translocation of cytoplasmic aquaporin 2 (AQP2) to the apical membrane. Clinically, the actions of lithium on renal tubular function are less clearly established. This study examined the effects of four weeks of lithium therapy on desmopressin (dDAVP)-stimulated urinary concentrating ability in healthy volunteers. METHODS: Eleven healthy volunteers underwent baseline urinary concentrating ability studies which were repeated following 4 weeks therapy with lithium carbonate (250 mg twice a day). Urinary osmolality, urinary AQP2 and cyclic adenosine monophosphate (cAMP) levels were measured following overnight fluid deprivation and after the administration of 40 microg of dDAVP. Baseline values were compared with results after 4 weeks of lithium therapy. RESULTS: Four weeks of lithium therapy reduced dDAVP-stimulated urinary concentrating ability (996 +/- 27 to 945 +/- 26 mOsm/kg) (P < 0.05) and this was associated with significant reduction in urinary AQP2 excretion (99.2 +/- 10.0 to 77.8 +/- 7.4 fmol/micromol creatinine) (P < 0.05) and urinary cAMP excretion (3188 +/- 376 to 2212 +/- 378 units) (P < 0.01). CONCLUSION: Four weeks of lithium therapy in healthy volunteers produced a small but significant reduction in dDAVP-stimulated urinary concentrating ability, which appears to be mediated by the inhibition of AVP-stimulated translocation of cytoplasmic AQP2 to the collecting tubule apical membrane via inhibition of adenyl cyclase.