EFFECT OF INHALED NITRIC OXIDE ON NEURODEVELOPMENTAL OUTCOMES IN PREMATURE INFANTS

Premature infants treated with inhaled nitric oxide have improved neurodevelopmental outcomes at age 2, according to Karen K. L. Mestan, MD, and colleagues. “Not only does nitric oxide extend life in a large group of premature infants, it also improves the quality of life for the children and their parents,” commented Michael Schreiber, MD, study director. Results of the study were published in the July 7 New England Journal of Medicine.

A total of 207 premature infants requiring mechanical ventilation and surfactant replacement therapy were randomly assigned to treatment with inhaled nitric oxide or placebo. At age 2, 168 were still alive, 29 of whom were lost to follow-up; 70 had received inhaled nitric oxide and 68 had received placebo. At follow-up, the children were screened for cerebral palsy, blindness, hearing loss, and developmental delay, defined by a score of at least 2 standard deviations below the mean without disability on the Mental or Psychomotor Developmental Index of the Bayley Scales of Infant Development II.

According to the results of the investigation, “Patients treated with inhaled nitric oxide had approximately half the risk of having an abnormal neurodevelopmental outcome as those in the placebo group.” Thirty-four percent of patients in the placebo group had developmental delays compared with 16% in the inhaled nitric oxide group.

Dr. Mestan and her colleagues also remarked that “the correlation of developmental assessments with ultimate developmental achievement is greater for assessments at 5 and 8 years of age. Consequently, continued follow-up of this cohort will provide data on the robustness of the effect of inhaled nitric oxide on neurodevelopment.”

They suggested that improved somatic growth and better health in the inhaled nitric oxide group might lead to better neurodevelopment. Also, “treatment may have directly affected the brain through mechanisms involving the cerebral vasculature or neuronal maturation.”

The researchers said that further research is necessary to define the appropriate dose of inhaled nitric oxide and the optimal duration of treatment in premature infants.

Mestan KKL, Marks JD, Hecox K, et al. Neurodevelopmental outcomes of premature infants treated with inhaled nitric oxide. N Engl J Med. 2005;353:23-32.

IS RACE ASSOCIATED WITH STROKE SURVIVAL?

Black people are more likely to survive a first stroke than their white counterparts, according to Charles D. A. Wolfe, MD, and colleagues. These findings remained after socioeconomic status, age, and stroke subtype were controlled for, they reported in the August 20 edition of BMJ.

The researchers assessed 2,321 patients (1,721 white, 414 black, 186 other) from the South London Stroke Register, examining sociodemographic factors, risk factors for stroke and their management, severity of stroke, and acute service provision factors. Kaplan-Meier curves, log rank test, and Cox proportional hazards model were used to analyze survival.

Results indicated that although black patients were more likely to be admitted to a stroke unit, they were more likely to survive a stroke than were white patients. Mean survival among black patients was 39.3 months, compared with 31.2 months among white patients. Kaplan-Meier survival curves were similar for white and black people younger than 65; however, the researchers observed a difference in favor of black people older than 65. Likewise, survival curves were similar for black and white patients with a prior Barthel score of less than 15, but there was a difference in favor of black patients with a score between 15 and 20.

Compared with white patients, fewer black patients had a high alcohol intake or were current smokers. “High blood pressure and diabetes were more commonly observed in black people, with the reverse for ischemic heart disease, atrial fibrillation, and transient ischemic attack,” said the researchers. Overall, patients who were current smokers had poorer survival, as did those with atrial fibrillation and/or diabetes. Admission to a stroke unit had no impact on survival.

“It seems that black people have better access to stroke unit care and more active management of some modifiable risk factors for stroke. A healthy migrant population from Africa and the Caribbean may confer some survival advantage,” speculated the researchers, but “more detailed measures of socioeconomic status and education need to be incorporated into future studies to identify the contribution of such factors on survival.”

Wolfe CD, Smeeton NC, Coshall C, et al. Survival differences after stroke in a multiethnic population: follow-up study with the south London stroke register. BMJ. 2005;331:431-433.

RECOGNIZING SYMPTOMS OF RIGHT AND LEFT HEMISPHERIC STROKE

Symptoms of right hemispheric stroke appear to be underrecognized by patients and physicians, according to Christian Foerch, MD, and colleagues. This, in turn, leads to differences in the subsequent management of such patients, they said. Results of their study are published in the July 30 Lancet.

The researchers examined data obtained from a large, hospital-based stroke registry in Germany. They identified 11,328 patients who had left hemispheric events and 8,769 patients who had right hemispheric lesions. Left hemispheric events were reported more frequently in patients with transient ischemic attack and ischemic stroke, but not in those with intracerebral hemorrhage. The researchers noted that the difference between recognition of symptoms of left hemispheric stroke and those of right hemispheric stroke increases with patient age and decreases with severity of symptoms and time to admission.

Dr. Foerch and his colleagues found that more patients with left hemispheric events were admitted within three hours of stroke symptom onset and/or were treated with thrombolysis. They concluded that “difficulties in recognition of symptoms due to right hemispheric stroke pose specific challenges for the effort to further optimize stroke management, particularly in the critical early hours of stroke.”

In an accompanying editorial, John N. Fink, MB, ChB, FRACP, said that patients, their family members, and physicians “might be more likely to recognize a disturbance of speech or language from left-hemisphere ischemia than a more difficult-to-define cognitive deficit or apraxia from a corresponding lesion on the right.”

One reason for this is that in the community, there are “significant deficiencies in knowledge about the signs and symptoms of stroke; non-language cognitive deficits in particular get little mention.”

Dr. Fink said that “failure to recognize the cause of these impairments might have important consequences, including an influence on relationships, maintenance of employment, appropriate safety advice about driving a motor vehicle, and access to rehabilitation services.”

Foerch C, Misselwitz B, Sitzer M, et al. Difference in recognition of right and left hemispheric stroke. Lancet. 2005; 366:392-393.
Fink JN. Underdiagnosis of right-brain stroke. Lancet. 2005;366:349-350.

PREDICTING RISK OF STROKE AFTER TRANSIENT ISCHEMIC ATTACK

Risk of stroke in the week following a transient ischemic attack can be highly predictable, according to Peter M. Rothwell, MD, PhD, and colleagues. The researchers developed a 6-point score in an attempt to improve the management of patients with transient ischemic attacks and to predict which patients are at highest early risk of stroke. Results of their study were published in the July 2 Lancet.

Using a cohort of patients with probable or definite transient ischemic attack from the Oxfordshire Community Stroke Project, the researchers created a 6-point scale dubbed ABCD (age, blood pressure, clinical features, and duration of symptoms in minutes). The score was then validated in a similar population-based cohort from the Oxford Vascular Study (OXVASC). The investigative team also assessed clinical usefulness to front-line health services by using the score to stratify all patients with suspected TIA referred to OXVASC and to a hospital-based weekly transient ischemic attack clinic.

According to Dr. Rothwell and colleagues, the ABCD score “was highly predictive of seven-day risk of stroke in OXVASC patients with probable or definite transient ischemic attack, in the OXVASC population-based cohort of all referrals with suspected transient ischemic attack, and in the hospital-based weekly transient ischemic attack clinic-referred cohort.”

Among 101 OXVASC patients with suspected transient ischemic attack, 19 of 20 strokes occurred in those patients with a score of 5 or greater. Seven-day risk of stroke was 0.4% in 274 patients with a score of less than 5, 12.1% in 66 patients with a score of 5, and 31.4% in 35 patients with a score of 6. Among patients referred to a hospital-based transient ischemic attack clinic, 14 patients with a score of 4 or greater had a stroke before their scheduled appointment.

Dr. Rothwell and his colleagues concluded that “the current score can be used in routine clinical practice to identify high-risk individuals who require emergency investigation and treatment.”

Rothwell PM, Giles MF, Flossmann E, et al. A simple score (ABCD) to identify individuals at high early risk of stroke after transient ischaemic attack. Lancet. 2005;366:29-36.

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