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Biomedical subjects

S A Mayer

Publications and source records attributed to S A Mayer.

At least 37 records · Page 2Linked to original sources
PubMed2000

Quadrigeminal variant of perimesencephalic nonaneurysmal subarachnoid hemorrhage.

OBJECTIVE: Perimesencephalic nonaneurysmal subarachnoid hemorrhage (PNSH) is a benign entity with a low risk of rebleeding. The most widely accepted definition emphasizes the presence of blood ventral to the midbrain or pons on early computed tomography. We sought to determine the frequency of PNSH with blood centered in the quadrigeminal cistern. METHODS: We reviewed a prospectively collected database of all patients admitted to our institution over a 2.5-year period with subarachnoid hemorrhage (SAH) and identified PNSH patients from early computed tomographic scans and negative four-vessel angiograms. RESULTS: Of 220 SAH patients, we identified 9 with PNSH. Two (22%) of these patients had SAH centered in the quadrigeminal cistern without pretruncal blood, negative repeat angiograms, and an uncomplicated clinical course. CONCLUSION: Quadrigeminal SAH is a variant of PNSH that is not well described in the literature. It may comprise up to one-fifth of PNSH cases and carries a similar benign prognosis.

Aged↗
PubMed2000

Cost and outcome of mechanical ventilation for life-threatening stroke.

BACKGROUND AND PURPOSE: Hospital mortality rates of 50% to 90% have been reported for stroke patients treated with mechanical ventilation. These data have raised serious questions about the cost-effectiveness of this intervention. We sought to determine how often stroke patients are mechanically ventilated, identify predictors of 30-day survival among ventilated patients, and evaluate the cost-effectiveness of this intervention. METHODS: We identified mechanically ventilated patients in a population-based multiethnic cohort of 510 incidence stroke patients who were hospitalized between July 1993 and June 1996. Factors affecting 30-day survival were identified in a multiple logistic regression analysis. We calculated the cost per patient discharged alive, life-year saved, and quality-adjusted life-year saved using a zero-cost, zero-life assumption. RESULTS: Ten percent of patients (n=52) were mechanically ventilated. Thirty-day mortality was 65% overall and did not differ significantly by stroke subtype. Glasgow Coma Scale score on the day of intubation (P:<0.01) and subsequent neurological deterioration (P:=0.02) were identified as predictors of 30-day mortality. The cost (1996 US dollars) of hospitalization per patient discharged alive was $89 400; the cost per year of life saved was $37 600; and the cost per quality-adjusted life-year saved was $174 200. Functional status of most survivors was poor; at 6 months, half were severely disabled and completely dependent. In a worst-case scenario of quality of life preferences, mechanical ventilation resulted in a net deficit of meaningful survival. CONCLUSIONS: Two thirds of mechanically ventilated stroke patients die during their hospitalization, and most survivors are severely disabled. Survival is particularly unlikely if patients are deeply comatose or clinically deteriorate after intubation. In our multiethnic urban population, mechanical ventilation for stroke was relatively cost-effective for extending life but not for preserving quality of life.

Adult↗
PubMed2000

Effect of hypervolemic therapy on cerebral blood flow after subarachnoid hemorrhage : a randomized controlled trial.

BACKGROUND AND PURPOSE: Cerebral blood flow (CBF) is reduced after subarachnoid hemorrhage (SAH), and symptomatic vasospasm is a major cause of morbidity and mortality. Volume expansion has been reported to increase CBF after SAH, but CBF values in hypervolemic (HV) and normovolemic (NV) subjects have never been directly compared. METHODS: On the day after aneurysm clipping, we randomly assigned 82 patients to receive HV or NV fluid management until SAH day 14. In addition to 80 mL/h of isotonic crystalloid, 250 mL of 5% albumin solution was given every 2 hours to maintain normal (NV group, n=41) or elevated (HV group, n=41) cardiac filling pressures. CBF ((133)xenon clearance) was measured before randomization and approximately every 3 days thereafter (mean, 4.5 studies per patient). RESULTS: HV patients received significantly more fluid and had higher pulmonary artery diastolic and central venous pressures than NV patients, but there was no effect on net fluid balance or on blood volume measured on the third postoperative day. There was no difference in mean global CBF during the treatment period between HV and NV patients (P=0.55, random-effects model). Symptomatic vasospasm occurred in 20% of patients in each group and was associated with reduced minimum regional CBF values (P=0.04). However, there was also no difference in minimum regional CBF between the 2 treatment groups. CONCLUSIONS: HV therapy resulted in increased cardiac filling pressures and fluid intake but did not increase CBF or blood volume compared with NV therapy. Although careful fluid management to avoid hypovolemia may reduce the risk of delayed cerebral ischemia after SAH, prophylactic HV therapy is unlikely to confer an additional benefit.

Adult↗
PubMed1999

Withdrawal of life support in the neurological intensive care unit.

OBJECTIVE: To describe the frequency and clinical course of terminal extubation in the neurological intensive care unit, to identify factors that influence the decision to withdraw life support, and to evaluate the experiences of surrogate decision-makers. BACKGROUND: The right of patients to refuse life-prolonging treatment is widely accepted. However, it is unknown how frequently critically ill neurologic patients are removed from life support, and practice guidelines for withdrawing mechanical ventilation remain poorly defined. METHODS: We reviewed the medical records of all patients cared for by the Columbia-Presbyterian neurocritical care service over a 3-year period who died, and identified a subgroup of non-brain-dead patients who were terminally extubated. We retrospectively analyzed the clinical course of these patients and interviewed their surrogate decision-makers. RESULTS: Of 74 non-brain-dead patients, 32 (43%) were terminally extubated. Hispanic and white patients were more likely to be extubated than were African American patients (p = 0.02). The median duration of survival after extubation was 7.5 hours; 25% died within 1 hour, and 69% within 24 hours. Depth of coma did not predict the duration of survival after extubation. The most frequent signs after extubation were agonal or labored breathing (59%) and tachypnea (34%). Morphine or fentanyl was given to relieve respiratory distress in 68% of cases; the average dose of morphine was 6.3 mg/hour (range 2.5 to 20 mg/hour). In a structured interview of 24 surrogate decision-makers, 88% were satisfied or very satisfied with the overall process, and 75% felt the patient suffered minimally before death; all but one (96%) said that they would repeat the decision to withdraw life support. CONCLUSIONS: Forty-three percent of our non-brain-dead patients who died were terminally extubated. The duration of survival after extubation exceeded 24 hours in one third, and was not predicted by level of consciousness. Two thirds of patients were treated with opioids for agonal respiratory distress. Most surrogate decision-makers were comfortable and satisfied with the process of withdrawing care.

Aged↗
PubMed1999

Myocardial injury and left ventricular performance after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Electrocardiographic abnormalities and elevations of the creatine kinase myocardial isoenzyme (CK-MB) occur frequently after subarachnoid hemorrhage. In some patients, a reversible and presumably neurogenic form of left ventricular dysfunction is demonstrated by echocardiography. It is not known whether cardiac injury of this type adversely affects cardiovascular hemodynamic performance. METHODS: We retrospectively studied 72 patients admitted to our neuro-ICU for aneurysmal subarachnoid hemorrhage over a 2.5-year period. We selected patients who met the following criteria: (1) CK-MB levels measured within 3 days of onset, (2) pulmonary artery catheter placed, (3) echocardiogram performed, and (4) no history of preexisting cardiac disease. Hemodynamic profiles were recorded on the day after surgery (n=67) or on the day of echocardiography (n=5) if surgery was not performed (mean, 3. 3+/-1.7 days after onset). The severity of cardiac injury was classified as none (peak CK-MB <1%, n=36), mild (peak CK-MB 1% to 2%, n=21), moderate (peak CK-MB >2%, n=6), or severe (abnormal left ventricular wall motion, n=9). RESULTS: Abnormal left ventricular wall motion occurred exclusively in patients with peak CK-MB levels >2% (P<0.0001), poor neurological grade (P=0.002), and female sex (P=0.02). Left ventricular stroke volume index and stroke work index were elevated above the normal range in patients with peak CK-MB levels <1% and fell progressively as the severity of cardiac injury increased, with mean values for patients with abnormal wall motion below normal (both P<0.0001 by ANOVA). Cardiac index followed a similar trend, but the effect was less pronounced (P<0.0001). Using forward stepwise multiple logistic regression, we found that thick subarachnoid clot on the admission CT scan (odds ratio, 1.9; 95% confidence interval [95% CI], 1.0 to 3.4; P=0.04) and depressed cardiac index (odds ratio, 2.1; 95% CI, 1.0 to 4.1; P=0.04) were independent predictors of symptomatic vasospasm. CONCLUSIONS: Myocardial enzyme release and echocardiographic wall motion abnormalities are associated with impaired left ventricular performance after subarachnoid hemorrhage. In severely affected patients, reduction of cardiac output from normally elevated levels may increase the risk of cerebral ischemia related to vasospasm.

Acute Disease↗
PubMed1998

Enhancer elements activate the weak 3' splice site of alpha-tropomyosin exon 2.

We have identified four purine-rich sequences that act as splicing enhancer elements to activate the weak 3' splice site of alpha-tropomyosin exon 2. These elements also activate the splicing of heterologous substrates containing weak 3' splice sites or mutated 5' splice sites. However, they are unique in that they can activate splicing whether they are placed in an upstream or downstream exon, and the two central elements can function regardless of their position relative to one another. The presence of excess RNAs containing these enhancers could effectively inhibit in vitro pre-mRNA splicing reactions in a substrate-dependent manner and, at lower concentrations of competitor RNA, the addition of SR proteins could relieve the inhibition. However, when extracts were depleted by incubation with biotinylated exon 2 RNAs followed by passage over streptavidin agarose, SR proteins were not sufficient to restore splicing. Instead, both SR proteins and fractions containing a 110-kD protein were necessary to rescue splicing. Using gel mobility shift assays, we show that formation of stable enhancer-specific complexes on alpha-tropomyosin exon 2 requires the presence of both SR proteins and the 110-kD protein. By analogy to the doublesex exon enhancer elements in Drosophila, our results suggest that assembly of mammalian exon enhancer complexes requires both SR and non-SR proteins to activate selection of weak splice sites.

Alternative Splicing↗
PubMed1998

Effect of 5% albumin solution on sodium balance and blood volume after subarachnoid hemorrhage.

OBJECTIVE: Subarachnoid hemorrhage (SAH) predisposes patients to excessive natriuresis and volume contraction. We studied the effects of postoperative administration of 5% albumin solution on sodium balance and blood volume after SAH. We also sought to identify physiological variables that influence renal sodium excretion after SAH. METHODS: Forty-three patients with acute SAH were randomly assigned to receive hypervolemia or normovolemia treatment for a period of 7 days after aneurysm clipping. In addition to a base line infusion of normal saline solution (80 ml/hr), 250 ml of 5% albumin solution was administered every 2 hours for central venous pressure (CVP) values of < or =8 mm Hg (hypervolemia group, n = 19) or < or =5 mm Hg (normovolemia group, n = 24). RESULTS: Both groups demonstrated relative volume expansion in base line measurements. The hypervolemia group received significantly more total fluid, sodium, and 5% albumin solution than did the normovolemia group and had higher CVP values and serum albumin levels (all P < 0.02). Cumulative sodium balance was even in the hypervolemia group and persistently negative in the normovolemia group, because of sodium losses that occurred on Postoperative Days 2 and 3 (P = 0.03). In a multiple-regression analysis of all patients, 24-hour sodium balance correlated negatively with glomerular filtration rate (GFR) and positively with serum albumin levels, after correction for sodium intake (P < 0.0001). Hypervolemia therapy seemed to paradoxically lower GFR (P = 0.10) and had no effect on blood volume, which declined by 10% in both groups. Pulmonary edema requiring diuresis occurred in only one patient in the hypervolemia group. CONCLUSION: Supplemental 5% albumin solution given to maintain CVP values of >8 mm Hg prevented sodium and fluid losses but did not have an impact on blood volume in our patients, who were hypervolemic in base line measurements. The natriuresis that occurs after SAH may be mediated in part by elevations of GFR. In addition to acting as a colloid volume expander, 5% albumin solution lowers the GFR and promotes renal sodium retention after SAH. These properties may limit the amount of total fluid required to maintain a given CVP value and hence may minimize the frequency of pulmonary edema.

Adult↗
PubMed1998

Diagnosis and monitoring of cerebral hyperfusion after carotid endarterectomy with single photon emission computed tomography: case report.

OBJECTIVE AND IMPORTANCE: Focal neurological deficits after carotid endarterectomy may result from ischemia or hyperperfusion. The usefulness of single photon emission computed tomography (SPECT) for differentiating between these two mechanisms has not been previously emphasized. CLINICAL PRESENTATION: An 83-year-old man experienced dysarthria and left-sided weakness immediately after undergoing endarterectomy of the right internal carotid artery. The results of computed tomography of the head were normal, and transcranial Doppler sonography showed symmetrically elevated velocities in both middle cerebral arteries. On the 1st postoperative day, the patient's deficits worsened in parallel with spontaneous increases in blood pressure, and blood pressure reduction with labetalol resulted in clinical improvement. INTERVENTION: On the 2nd postoperative day, technetium-99-hexametazime SPECT demonstrated markedly increased flow in the right basal ganglia and inferior frontal cortex, confirming the diagnosis of cerebral hyperperfusion. The patient's deficits continued to improve with antihypertensive therapy, and SPECT performed 7 and 48 days after surgery showed gradual normalization of the focal hyperemia. CONCLUSION: SPECT can be used to diagnose and monitor cerebral hyperperfusion after carotid endarterectomy and may be of particular value for differentiating hyperperfusion from ischemia when characteristic computed tomographic and transcranial Doppler sonographic findings are absent.

Aged↗
PubMed1998

Complex intracranial aneurysms: combined operative and endovascular approaches.

OBJECTIVE: Endovascular management of complex intracranial aneurysms is increasingly being considered as an alternative to standard surgical clipping. However, little attention has been paid to the complementary nature of surgery and endovascular therapy. METHODS: Between September 1992 and May 1997, 12 patients with complex intracranial aneurysms were treated with combined operative and endovascular methods. Seven patients demonstrated subarachnoid hemorrhage (two of Grade II, two of Grade III, and three of Grade IV). Five patients demonstrated unruptured aneurysms, i.e., three giant aneurysms (one vertebrobasilar junction aneurysm, one middle cerebral artery bifurcation aneurysm, and one internal carotid artery-ophthalmic artery aneurysm), one large internal carotid artery-ophthalmic artery aneurysm, and one middle cerebral artery serpentine aneurysm. Management strategies involved either surgery followed by endovascular therapy (S-E; n = 5) or endovascular therapy followed by surgery (E-S; n = 7). S-E paradigms included aneurysm exploration followed by endovascular treatment (S-E1; n = 3), partial aneurysm clipping followed by endovascular aneurysm packing (S-E2; n = 1), and extracranial-to-intracranial bypass followed by endovascular parent vessel occlusion (S-E3; n = 1). E-S paradigms included superselective angiography followed by surgical clipping (E-S1; n = 2), Guglielmi detachable coil partial dome packing followed by delayed surgical clipping (E-S2; n = 2), proximal temporary vessel balloon occlusion followed by aneurysm clipping (E-S3; n = 2), and proximal permanent vessel occlusion followed by surgical aneurysm decompression for mass effect treatment (E-S4; n = 1). RESULTS: Eleven aneurysms (92%) were completely eliminated. The remaining aneurysm was 90% obliterated and remained quiescent at the 34-month follow-up examination, despite presenting with subarachnoid hemorrhage. No patient experienced repeat bleeding (follow-up period, 23+/-28 mo). There were no deaths. One patient achieved a fair outcome (Glasgow Outcome Scale score of III); all other patients experienced excellent outcomes (Glasgow Outcome Scale score of I). In all cases, the aneurysm management paradigm chosen had a positive effect on definitive therapy. CONCLUSION: Several factors can contribute to the complexity of intracranial aneurysms. Management strategies that combine operative and endovascular techniques in a complementary way, for the best possible outcomes for these patients, can be designed accordingly.

Adult↗
PubMed1998

Perilesional blood flow and edema formation in acute intracerebral hemorrhage: a SPECT study.

BACKGROUND AND PURPOSE: Secondary brain injury and edema formation contribute significantly to morbidity and mortality after intracerebral hemorrhage (ICH). The pathogenesis of this process is poorly understood. We sought to characterize alterations in perilesional blood flow that occur during the acute phase of ICH and to determine whether progressive enlargement of edema surrounding ICH is related to increased or decreased perfusion. METHODS: We performed paired consecutive CT and 99mTc-hexamethylpropylenamine oxime single-photon emission computed tomography (SPECT) scans during the acute (mean, 18 hours) and subacute (mean, 72 hours) phase of ICH in 23 patients. Hematoma and edema volumes were traced and calculated from CT images. SPECT-derived hypothetical flow deficit volumes (FDV) around each hematoma were calculated by measuring a "zero-flow" volume within a large perilesional region of interest (based on percent tracer count loss compared with the contralateral side) and subtracting the corresponding ICH volume. Patients with significant midline shift (>5 mm) or global blood flow reduction were excluded from the analysis. RESULTS: ICH volume (18 mL) did not change, mean edema volume increased by 36% (from 19 to 25 mL, P<0.0001), and mean FDV decreased by 55% (from 14 to 6 mL, P=0.0004) between the acute and subacute phases. Edema volume on the second CT scan correlated positively with FDV on the first SPECT scan (Spearman's p=0.48, P=0.02), and with the volume of reperfused perilesional tissue (FDVacute-FDVsubacute) (Spearman's p=0.41, P=0.05). Perilesional edema on CT always corresponded topographically with perfusion deficits on SPECT. In 4 patients, delayed focal hyperemia was identified in more peripheral cortical regions, but these areas appeared normal on CT. CONCLUSIONS: Perilesional blood flow normalizes from initially depressed levels as edema forms during the first 72 hours after ICH, and the eventual extent of edema correlates with the volume of reperfused tissue. These results suggest that the potential for perilesional ischemia is highest in the earliest hours after ICH onset and implicate reperfusion injury in the pathogenesis of perihematoma edema formation.

Acute Disease↗
PubMed1997

Functional crosstalk between exon enhancers, polypyrimidine tracts and branchpoint sequences.

We recently identified enhancer elements that activate the weak 3' splice site of alpha-tropomyosin exon 2 as well as a variety of heterologous weak 3' splice sites. To understand their mechanism of action, we devised an iterative selection strategy to identify functional pyrimidine tracts and branchpoint sequences in the presence or absence of enhancer elements. Surprisingly, we found that strong pyrimidine tracts were selected regardless of the presence of enhancer elements. However, the presence of enhancer elements resulted in the selection of multiple, non-consensus branchpoint sequences. Thus, enhancer elements apparently activate weak 3' splice sites primarily by increasing the efficiency of splicing of introns containing branchpoint sequences with less than optimal U2-branchpoint pairing arrangements. Comparison of consensus sequences from both our selection strategy and compilations of published intron sequences suggests that exon enhancer elements could be widespread and play an important role in the selection of 3' splice sites.

Animals↗
PubMed1997

Premature 3'-end formation of CBP1 mRNA results in the downregulation of cytochrome b mRNA during the induction of respiration in Saccharomyces cerevisiae.

The yeast mitochondrial genome encodes only seven major components of the respiratory chain and ATP synthase; more than 200 other mitochondrial proteins are encoded by nuclear genes. Thus, assembly of functional mitochondria requires coordinate expression of nuclear and mitochondrial genes. One example of coordinate regulation is the stabilization of mitochondrial COB (cytochrome b) mRNA by Cbp1, the product of the nuclear gene CBP1 (cytochrome b processing). CBP1 produces two types of transcripts with different 3' ends: full-length 2.2-kb transcripts and 1.2-kb transcripts truncated within the coding sequence of Cbp1. Upon induction of respiration, the steady-state level of the long transcripts decreases while that of the short transcripts increases reciprocally, an unexpected result since the product of the long transcripts is required for COB mRNA stability and thus for respiration. Here we have tested the hypothesis that the short transcripts, or proteins translated from the short transcripts, are also required for respiration. A protein translated from the short transcripts was not detected by Western analysis, although polysome gradient fractions were shown to contain both long and short CBP1 transcripts. A mutant strain in which production of the short transcripts was abolished showed wild-type growth properties, indicating that the short transcripts are not required for respiration. Due to mutation of the carbon source-responsive element, the long transcript level in the mutant strain did not decrease during induction of respiration. The mutant strain had increased levels of COB RNA, suggestive that production of short CBP1 transcripts is a mechanism for downregulation of the levels of long CBP1 transcripts, Cbp1, and COB mRNA during the induction of respiration.

Base Sequence↗
PubMed1997

Myasthenic crisis: clinical features, mortality, complications, and risk factors for prolonged intubation.

We retrospectively reviewed the hospital records of 53 patients admitted for 73 episodes of myasthenic crisis at Columbia-Presbyterian Medical Center over a period of 12 years, from 1983 to 1994. Median age at the onset of first crisis was 55 (range, 20 to 82), the ratio of women to men was 2:1, and the median interval from onset of symptoms to first crisis was 8 months. Infection (usually pneumonia or upper respiratory infection) was the most common precipitating factor (38%), followed by no obvious cause (30%) and aspiration (10%). Twenty-five percent of patients were extubated at 7 days, 50% at 13 days, and 75% at 31 days; the longest crisis exceeded 5 months. Using survival analysis and backward stepwise Cox regression, we identified three independent predictors of prolonged intubation: (1) pre-intubation serum bicarbonate > or = 30 mg/dl (p = 0.0004, relative hazard 4.5), (2) peak vital capacity day 1 to 6 post-intubation < 25 ml/kg (p = 0.001, relative hazard 2.9), and (3) age > 50 (p = 0.01, relative hazard 2.4). The proportion of patients intubated longer than 2 weeks was 0% among those with no risk factors, 21% with one risk factor, 46% with two risk factors, and 88% with three risk factors (p = 0.0004). Complications independently associated with prolonged intubation included atelectasis (p = 0.002), anemia treated with transfusion (p = 0.03), Clostridium difficile infection (p = 0.01), and congestive heart failure (p = 0.03). Three episodes of crisis were fatal, for a mortality rate of 4% (3/73); four additional patients died after extubation. All seven deaths were due to overwhelming medical comorbidity. Over half of those who survived were functionally dependent (home or institutionalized) at discharge. In addition to prospective controlled studies of immunotherapies, the prevention and treatment of medical complications offers the best opportunity for further improving the outcome of myasthenic crisis.

Adult↗
PubMed1997

Delayed posthypoxic demyelination. Association with arylsulfatase A deficiency and lactic acidosis on proton MR spectroscopy.

Delayed demyelination is a rare and poorly understood complication of hypoxic brain injury. A previous case report has suggested an association with mild-to-moderate deficiency of arylsulfatase A. We describe a 36-year-old man who recovered completely from an episode of hypoxia related to drug overdose, and 2 weeks later progressed from a confusional state to deep coma. MRI showed diffuse white matter signal changes, and brain biopsy demonstrated a noninflammatory demyelinating process. Proton magnetic resonance spectroscopy revealed elevated choline and lactate and reduced N-acetyl aspartate signal in the affected white matter, consistent with demyelination and a shift to anaerobic metabolism. Arylsulfatase A activity from peripheral leukocytes was approximately 50% of normal, consistent with a "pseudodeficiency" phenotype. These findings confirm the hypothesis that relative arylsulfatase A deficiency predisposes susceptible individuals to delayed posthypoxic leukoencephalopathy and implicates lactic acidosis in the pathogenesis of this disorder.

Acidosis, Lactic↗
PubMed1997

Early diagnosis and endovascular interventions for ischemic stroke.

In recent years there have been formidable advances in the war against stroke. The understanding and detection of stroke have undergone major progress at a rate previously unseen, partly due to major contributions from neuroradiology. Current routine neuroradiologic evaluation of acute stroke relies mainly on computed tomography scanning, although a number of radiologic modalities are becoming available that are based on various physical and chemical tissue properties, such as magnetic resonance imaging, single photon emission computed tomography, positron emission tomography, and magnetic resonance spectroscopy. All these new techniques allow the study of nervous tissue at the cellular and biochemical levels. A review of current diagnostic techniques for stroke follows in the first part of this article. The current status of endovascular therapy for ischemic stroke is reviewed in the second part of this article.

Angioplasty, Balloon↗
PubMed1996

Relationship between the volume of craniotomies for cerebral aneurysm performed at New York state hospitals and in-hospital mortality.

BACKGROUND AND PURPOSE: After a craniotomy for cerebral aneurysm, postoperative mortality can be significant. Previous studies have shown that hospitals performing frequent high-risk procedures (such as coronary artery bypass) have a lower mortality than hospitals where these procedures are performed infrequently. METHODS: The Statewide Planning and Research Cooperative System of the New York State Department of Health reviewed all discharges in New York State from 1987 through 1993 for the diagnoses of subarachnoid hemorrhage and/or cerebral aneurysm and for patients with the procedure code for craniotomy for ruptured or unruptured cerebral aneurysm. In-hospital mortality and length of stay were examined in relation to the volume of craniotomies for aneurysm performed at each individual hospital. RESULTS: A total of 15,376 discharges for subarachnoid hemorrhage and 5638 craniotomies for aneurysm were tabulated in 208 hospitals. For all patients who underwent craniotomy for ruptured cerebral aneurysm (n = 4034), there was a 43% (95% confidence interval, 29% to 57%) reduction in mortality rate in hospitals performing more than 30 craniotomies per year for cerebral aneurysm compared with hospitals performing less surgery (8.8% versus 15.5%, P < .0001). For all patients who underwent craniotomy for unruptured cerebral aneurysm (n = 1604), there was an identical 43% (95% confidence interval, 14% to 73%) reduction in mortality in hospitals performing more than 30 craniotomies per year for cerebral aneurysm (4.6% versus 8.1%, P = .0087). CONCLUSIONS: Hospitals that frequently perform aneurysm operations have lower mortality rates for patients undergoing craniotomy for cerebral aneurysm than hospitals that perform fewer operations.

Aneurysm, Ruptured↗
PubMed1996

Asymmetry of intracranial hemodynamics as an indicator of mass effect in acute intracerebral hemorrhage. A transcranial Doppler study.

BACKGROUND AND PURPOSE: Hematoma volume is an important determinant of outcome and predictor of clinical deterioration in patients with intracerebral hemorrhage. In many cases, worsening results from herniation due to compartmentalized pressure gradients. We used transcranial Doppler sonography (TCD) to assess the impact of hematoma volume on symmetry of intracranial hemodynamics in patients with acute intracerebral hemorrhage. The goal was to evaluate TCD as a noninvasive method for monitoring compartmentalized mass effect. METHODS: TCD was performed an average of 1.1 days (range, 0 to 3 days) after onset in 30 patients with supratentorial intracerebral hemorrhage. Hematoma, hematoma + edema, and intraventricular hemorrhage volumes were calculated from admission CT scans using computerized planimetry and were compared with combined TCD values from the middle cerebral and internal carotid arteries. RESULTS: Ipsilateral pulsatility indexes were consistently elevated and mean velocities consistently depressed when intracerebral hemorrhage volumes exceeded 25 mL. Compared with patients with small hemorrhages, those with large hemorrhages (> or = 25 mL, n = 10) had significantly higher ipsilateral pulsatility indexes (1.72 versus 1.13, P < .0001) and higher ratios of ipsilateral-to-contralateral pulsatility (1.29 versus 1.06, P = .001). The ratio of ipsilateral-to-contralateral mean velocity was similarly reduced in patients with large versus small hemorrhages (0.87 versus 1.06, P = .01), but this effect was less pronounced. In a multiple regression analysis, ipsilateral and contralateral pulsatility indexes correlated primarily with intraventricular hemorrhage volume (P < .001), whereas the ratio of ipsilateral-to-contralateral pulsatility correlated with total hemispheric lesion (hematoma + edema) volume (P = .003). CONCLUSIONS: Asymmetry of intracranial hemodynamics as assessed by TCD occurs when intracerebral hemorrhage volumes exceed 25 mL. Alterations of pulsatility index reflect intracranial lesion volume more reliably than mean velocity. Although pulsatility is strongly influenced by the presence of intraventricular blood, elevated ratios of ipsilateral-to-contralateral pulsatility correlate primarily with hemispheric lesion volume and may reflect compartmentalized intracranial pressure gradients.

Acute Disease↗