B-Type Natriuretic Peptide Assay Value Small in Assessing Hypertrophic Cardiomyopathy
Overlapping values among categories of heart failure severity and confounding variables of left ventricular wall thickness and age limit the value of plasma B-type natriuretic peptide in assessing patients with hypertrophic cardiomyopathy, said researchers from Minnesota in a report in this week’s issue of the journal Circulation (Circulation. 2004;109:984–989OpenUrl).
In the study, led by Barry J. Maron, MD, of the Hypertrophic Cardiomyopathy Center of the Minneapolis Heart Institute Foundation, researchers found that B-type natriuretic peptide had a statistically significant association to the degree of limitation suffered by 107 assessed patients with hypertrophic cardiomyopathy. The researchers noted that the marker had less value in distinguishing between patients with heart failure symptoms and those without than between those with no symptoms and those with severe symptoms.
They concluded that it is independently associated with the presence and magnitude of heart failure in this group of patients, but it has limitations. The researchers wrote, “Considerable variability in BNP [B-type natriuretic peptide] values among patients with different symptom magnitude, and the independent impact of confounding variables such as LV [left ventricular] wall thickness (and age), substantially restrict the practical clinical usefulness of BNP as a blood test marker for heart failure in HCM [hypertrophic cardiomyopathy].”
Clot Buster Plus Abciximab No Better Than Abciximab Alone in Percutaneous Coronary Intervention
Patients who received only abciximab fared as well as those who received abciximab along with the clot buster reteplase before undergoing a percutaneous intervention such as balloon angioplasty or stenting, said German researchers in a report in the February 25, 2004, issue of The Journal of the American Medical Association (JAMA. 2004;291:947–954OpenUrlCrossRefPubMed).
The researchers, led by Adnan Kastrati, MD, from the Deutsches Hezzentrum Technische Universitat in Munich, Germany, and colleagues in the Bavarian Reperfusion Alternatives Evaluation (BRAVE) study, wanted to find out if adding reteplase to the treatment could limit the infarct size in patients who had had a myocardial infarction. The study took place in the wake of others that had determined that patients who came to community facilities without catheterization capabilities benefited more from transferring to centers where percutaneous intervention could be undertaken than from remaining in place and undergoing treatment with clot-busting drugs.
Between May 3, 2001, and June 2, 2003, the researchers studied 253 patients admitted to 13 community hospitals without percutaneous intervention facilities (186 patients) and to 5 hospitals with such capabilities (67 patients). All arrived at the hospitals within 12 hours of the first symptoms of their myocardial infarction. One hundred twenty-five received the combination, and 128 received abciximab alone. All were then either transferred for a percutaneous intervention or went to the catheter lab for that treatment. Later, researchers measured the size of the infarct through single-photon emission computed tomography.
“The final infarct size of the left ventricle, the primary end point of the trial, was 13% in the reteplase plus abciximab group and 11.5% in the abciximab group,” the researchers reported. “The mean (average) difference in final infarct size of the left ventricle between the reteplase plus abciximab group and the abciximab group was 1.3%.”
There was no difference in the number of deaths, recurrent myocardial infarctions, or strokes between the two groups, but there was a trend toward more major bleeding incidents in the group that received abciximab and reteplase. The researchers found no benefit in adding the clot buster to abciximab in this group of patients.
In an accompanying editorial (JAMA. 2004;291:1000–1001), Michael Lincoff, MD, of The Cleveland Clinic Foundation, noted that even though primary percutaneous intervention is the gold standard for acute reperfusion therapy in such patients, there can be delays in achieving the treatment.
“Clinical judgment may compel a facilitated PCI approach (using medications before PCI),” he wrote. “Under those circumstances, the results of this randomized comparison between different regimens suggest that abciximab alone is at least as effective, with less bleeding risk, than the combination of the Gp IIb/IIIA blockade and reduced-dose fibrinolysis (abciximab and reteplase). The results of ongoing pivotal clinical trials should help to provide more definitive insights into how best to facilitate PCI during acute MI.”
In Favor of Home Blood Pressure Monitoring
Monitoring their blood pressure at home allowed patients to decrease the amount of drugs they took to reduce hypertension and thus to slightly lower their costs, said researchers in the February 25, 2004, issue of The Journal of the American Medical Association (JAMA. 2004;291:955–964OpenUrlCrossRefPubMed).
In this study from Belgium and Ireland, Jan A. Staessen, MD, PhD, from the University of Leuven in Belgium, and colleagues from the Treatment of Hypertension Based on Home or Office Blood Pressure (THOP) trial compared the value of self-measurement to conventional office blood pressure measurement in patients with hypertension. The research included 400 patients with diastolic readings of 99 mm Hg or higher—measured in the physicians’ offices.
The patients were then randomized to receive blood pressure treatment based on office blood pressure readings (197 patients) or home blood pressure measurements. Participants in the home monitoring group recorded about 6 measurements daily and averaged their daily blood pressure over a week. The measurements for the other group were the average of 3 readings at the doctor’s office. Patients were followed up for a year.
By the end of a year, 25.6% of patients who measured their blood pressure at home had ceased taking antihypertensive drugs, compared with 11.3% whose blood pressure readings were taken in the doctors’ offices. There was no significant difference in the number of patients requiring multiple drugs to control their hypertension.
“The final office, home and 24-hour ambulatory BP [blood pressure] measurements were higher in the home BP group than in the office BP group,” they reported.
The researchers summarized, “In conclusion, adjustment of antihypertensive treatment based on home BP instead of office BP led to less-intensive drug treatment and marginally lower costs but also to less BP control, with no differences in general well-being or left ventricular mass. Self-measurement helps to identify patients with white-coat hypertension [abnormal elevation of blood pressure only in the physician’s office]. Our findings support a step-wise strategy for the evaluation of BP in which self-measurement and ambulatory monitoring are complementary to conventional office measurement.”