Survival in treated idiopathic normal pressure hydrocephalus.

OBJECTIVE: To describe survival and causes of death in 979 treated iNPH patients from the Swedish Hydrocephalus Quality Registry (SHQR), and to examine the influence of comorbidities, symptom severity and postoperative outcome. METHODS: All 979 patients operated for iNPH 2004-2011 and registered in the SHQR were included. A matched control group of 4890 persons from the general population was selected by Statistics Sweden. Data from the Swedish Cause of Death Registry was obtained for patients and controls. RESULTS: At a median 5.9 (IQR 4.2-8.1) year follow-up, 37% of the iNPH patients and 23% of the controls had died. Mortality was increased in iNPH patients by a hazard ratio of 1.81, 95% CI 1.61-2.04, p < 0.001. More pronounced symptoms in the preoperative ordinal gait scale and the Mini-mental State Examination were the most important independent predictors of mortality along with the prevalence of heart disease. Patients who improved in both the gait scale and in the modified Rankin Scale postoperatively (n = 144) had a similar survival as the general population (p = 0.391). Deaths due to cerebrovascular disease or dementia were more common in iNPH patients, while more controls died because of neoplasms or disorders of the circulatory system. CONCLUSIONS: Mortality in operated iNPH patients is 1.8 times increased compared to the general population, a lower figure than previously reported. The survival of iNPH patients who improve in gait and functional independence is similar to that of the general population, indicating that shunt surgery for iNPH, besides improving symptoms and signs, can normalize survival.

Incidence, Comorbidities, and Mortality in Idiopathic Normal Pressure Hydrocephalus.

OBJECT: To investigate the incidence, comorbidities, mortality, and causes of death in idiopathic normal pressure hydrocephalus (iNPH). METHODS: A cohort of 536 patients with possible NPH from a defined population with a median follow-up time of 5.1 years, (range 0.04-19.9 years) was included in the study. Patients were evaluated by brain imaging and intraventricular pressure monitoring, with a brain biopsy specimen immunostained against amyloid-ß and hyperphosphorylated τ. Hospital records were reviewed for vascular diseases and type 2 diabetes mellitus (T2DM). Death certificates and yearly population of the catchment area were obtained from national registries. RESULTS: A total of 283 patients had a clinical diagnosis of iNPH, leading to a median annual incidence of 1.58 iNPH patients per 100,000 inhabitants (range, 0.8-4.5). Alzeimer disease-related brain biopsy findings were less frequent in iNPH patients than in non-iNPH patients (P < 0.05). An overrepresentation of hypertension (52% vs. 33%, P < 0.001) and T2DM (23% vs. 13%, P = 0.002) was noted in iNPH patients. Age (hazard ratio [HR] 1.04/year, 95% confidence interval [CI] 1.03-1.06, P < 0.001) and T2DM (HR 1.63, 95% CI 1.23-2.16, P < 0.001) increased the risk of death in the iNPH patients and in the total population. iNPH was associated with decreased risk of death (HR 0.63, 95% CI 0.50-0.78, P < 0.001). The most frequent causes of death were cardiovascular and cerebrovascular disease. Dementia as a cause of death was more common in non-iNPH patients (27% vs. 10%, P < 0.001). CONCLUSIONS: Hypertension and T2DM are common in iNPH and the latter causes excess mortality in the affected patients.

Subdural hematomas in 1846 patients with shunted idiopathic normal pressure hydrocephalus: treatment and long-term survival.

OBJECTIVE Subdural hematoma (SDH) is the most common serious adverse event in patients with shunts. Adjustable shunts are used with increasing frequency and make it possible to noninvasively treat postoperative SDH. The objective of this study was to describe the prevalence and treatment preferences of SDHs, based on fixed or adjustable shunt valves, in a national cohort of patients with shunted idiopathic normal pressure hydrocephalus (iNPH), as well as to evaluate the effect of SDH and treatment on long-term survival. METHODS Patients with iNPH who received a CSF shunt in Sweden from 2004 to 2015 were included in a prospective quality registry (n = 1846) and followed regarding SDH, its treatment, and mortality. The treatment of SDH was categorized into surgery, opening pressure adjustments, or no treatment. RESULTS During the study period, the proportion of adjustable shunts increased from 75% to 95%. Ten percent (n = 184) of the patients developed an SDH. In 103 patients, treatment was solely opening pressure adjustment. Surgical treatment was used in 66 cases (36%), and 15 (8%) received no treatment. In patients with fixed shunt valves, 90% (n = 17) of SDHs were treated surgically compared with 30% (n = 49) in patients with adjustable shunts (p < 0.001). There was no difference in long-term patient survival between the SDH and non-SDH groups or between different treatments. CONCLUSIONS SDH remains a common complication after shunt surgery, but adjustable shunts reduced the need for surgical interventions. SDH and treatment did not significantly affect survival in this patient group, thus the noninvasive treatment offered by adjustable shunts considerably reduces the level of severity for this common adverse event.

Outcome of Surgery for Idiopathic Normal Pressure Hydrocephalus: Role of Preoperative Static and Pulsatile Intracranial Pressure.

OBJECTIVES: To examine the outcome of surgery for idiopathic normal-pressure hydrocephalus (iNPH) and how outcome relates to the preoperative static and pulsatile intracranial pressure (ICP). METHODS: An observational cohort study included all patients with iNPH managed at our department during the years 2002-2012 in whom overnight ICP monitoring was part of the preoperative work-up. Clinical data were retrieved from a quality registry and ICP scores from a pressure database. RESULTS: The study included 472 patients, 316 in the surgery group and 156 in the nonsurgery group. Among those treated surgically, 278 (90%) showed clinical improvement (Responders) whereas 32 (10%) had no improvement (Nonresponders). Among Responders, only about one third reached the best clinical scores; moreover, the difference in clinical score between Responders and Nonresponders declined with time after surgery, particularly after 3-4 years. The surgery was accompanied by acute intracranial hematomas in 11 patients (3.5%), of whom 4 (1.3%) died. Survival (age at death) was significantly greater among the Responders than in Nonresponders. Although the static ICP was normal in all patients, the pulsatile ICP was significantly greater in Responders than in Non-responders. CONCLUSIONS: The pulsatile ICP was greater in shunt Responders than Nonresponders. Although the clinical improvement declined over time and the majority did not experience complete relief of symptoms, shunt Responders lived significantly longer than Nonresponders. The present observations suggest that the current surgical treatment regimens for iNPH (primarily shunt surgery) address only some aspects of the disease process, in particular the aspect of brain water disturbance.

Systematic review of the outcome of shunt surgery in idiopathic normal-pressure hydrocephalus.

INTRODUCTION: Early surgical series of shunt insertion for idiopathic normal-pressure hydrocephalus reported a low rate of short-term improvement with a relatively high rate of mortality and morbidity; subsequently shunt insertion was recommended for patients in whom there is favourable risk-to-benefit ratio. METHODS: Bibliographic search for studies that objectively assessed the outcome following shunt insertion in idiopathic normal-pressure hydrocephalus was done; the aim was to estimate the outcome of shunt insertion in terms of improvement rates and associated mortality and morbidity. RESULTS: A total of 64 studies of 3,063 patients were reviewed. Positive improvement following shunt insertion was reported in an average of 71 % of patients with an average 1 % mortality. Results from studies published in the last 5 years showed 82 % improvement following shunt insertion, mortality of 0.2 %, and combined common complications rate of 8.2 %. CONCLUSION: When patients are properly selected, shunt insertion is a safe and effective management of idiopathic normal-pressure hydrocephalus with a prolonged positive outcome.

Cerebrospinal fluid dynamics and long-term survival of the Strata valve in idiopathic normal pressure hydrocephalus.

OBJECTIVE: Cerebrospinal fluid (CSF) dynamics and long-term shunt survival of the Strata CSF shunt were evaluated in patients with idiopathic normal pressure hydrocephalus (INPH). SUBJECTS AND METHODS: Seventy-two patients with INPH received a Strata valve. A CSF infusion test, neuroimaging and video recording of gait were performed at baseline and at 6 months (n = 68) after surgery. Long-term shunt survivals were obtained from patient records. RESULTS: The shunt survival at 1 year was 94% and at 3 years 92.5%. Forty-nine patients (72%) had an improved gait. Two patients were improved despite non-functioning shunts, indicating a possible placebo response. Nineteen patients were not improved at the 6-month follow-up. The shunt tests revealed a functioning shunt in 12; thus, unnecessary shunt revisions could be avoided. Seventeen patients showed a siphoning effect. Shunt revisions were made in six patients. Eight hygromas/subdural hematomas were found. CONCLUSIONS: The long-term survival of the Strata valves was good, and a concern of complications is not a reason to exclude elderly with INPH from shunt surgery. Studies are needed to evaluate pros and cons of the anti-siphon device. Using a CSF shunt test, unnecessary shunt revisions may be avoided.

Extended long-term (> 5 years) outcome of cerebrospinal fluid shunting in idiopathic normal pressure hydrocephalus.

BACKGROUND: Shunt surgery has been established as the only durable and effective treatment for idiopathic normal pressure hydrocephalus. OBJECTIVE: We evaluated the "extended" long-term follow-up (> 5 years) in a prospective study cohort who underwent shunting between 1990 and 1995. A secondary objective was to determine the cause of death in these patients. METHODS: Fifty-one patients were included after confirmation of the diagnosis by extensive clinical and diagnostic investigations. Surgery included ventriculoatrial or ventriculoperitoneal shunting with differential pressure valves in the majority of patients. For each of the cardinal symptoms, postoperative outcome was assessed separately with the Krauss Improvement Index, yielding a value between 0 (no benefit) and 1 (optimal benefit) for the overall outcome. RESULTS: Mean age at surgery was 70.2 years (range, 50-87 years). Thirty patients were women, and 21 were men. Short-term (18.8 +/- 16.6 months) follow-up was available for 50 patients. The Krauss Improvement Index was 0.66 +/- 0.28. Long-term (80.9 +/- 51.6 months) follow-up was available for 34 patients. The Krauss Improvement Index was 0.64 +/-0.33. Twenty-nine patients died during the long-term follow-up at a mean age of 75.8 years (range, 55-95 years). The major causes of death were cardiovascular disorders: cardiac failure (n = 7) and cerebral ischemia (n = 12). Other causes were pneumonia (n = 2), acute respiratory distress syndrome (n = 1), pulmonary embolism (n = 1), cancer (n = 2), renal failure (n = 1), and unknown (n = 3). There was no shunt-related mortality. CONCLUSION: Idiopathic normal pressure hydrocephalus patients may benefit from shunting over the long term when rigorous selection criteria are applied. Shunt-related mortality is negligible. The main cause of death is vascular comorbidity.

Screening tests for normal-pressure hydrocephalus: sensitivity, specificity, and cost.

OBJECT: Many tests have been proposed to help choose candidates for shunt insertion in cases of suspected normal-pressure hydrocephalus (NPH). It is unclear what sensitivity and specificity a prospective test must have to improve outcomes, compared with the results of automatic shunt insertion. METHODS: The authors adapted the decision analysis model used in a companion article to allow for application of a screening test. Using the reported sensitivities and specificities of several such tests, they evaluated the effects such tests would have on the expected outcome of an average 65-year-old patient with moderate dementia. They also evaluated the cost-effectiveness of a theoretical screening test with superior sensitivity and specificity. CONCLUSIONS: Although external lumbar drainage comes quite close, none of the screening tests reported to date have sufficient sensitivity and specificity to improve expected outcome in an average candidate, compared with the results of automatic shunt placement in cases of suspected NPH. In addition, even a theoretically improved test would need to be considerably less expensive than prolonged lumbar drainage to be cost-effective in clinical practice.