Asymptomatic Left Ventricular Systolic Dysfunction—A Pending Disaster
Even mild, asymptomatic left ventricular systolic dysfunction increases the risk of congestive heart failure and death, said researchers from the famous Framingham Heart Study in a report in this week’s issue of the journal Circulation (Circulation. 2003;108:977–982OpenUrl).
Researchers led by Thomas J. Wang, MD, of the Massachusetts General Hospital, Boston, Mass, studied 4257 participants in the Framingham Study who had undergone routine echocardiography. Of these, 6% of the men and 0.8% of the women had asymptomatic left ventricular systolic dysfunction. During the 12 years of follow-up, subjects with normal left ventricular function greater than 50% developed congestive heart failure at a rate of 0.7 per 100 person-years. Those with asymptomatic left ventricular systolic dysfunction developed the disorder at a rate of 5.8 per 100 person-years. With adjustment for cardiovascular disease risk factors, the hazard ratio for congestive heart failure among patients with left ventricular dysfunction was 4.7 compared to those with normal heart function.
Asymptomatic left ventricular systolic dysfunction was also associated with an increased risk of death. Median survival among those with the dysfunction was 7.1 years. The researchers concluded: “Individuals with ALVD [asymptomatic left ventricular systolic dysfunction] in the community are at high risk of CHF [congestive heart failure] and death, even when only mild impairment of EF [ejection fraction] is present. Additional studies are needed to define optimal therapy for mild ALVD.”
Mismatch in Aortic Valve Replacement Can Increase Short-Term Mortality
When the prosthesis used in aortic valve replacement is too small for the patient’s body size, it increases the risk of death in the short term, said researchers from Quebec Heart Institute/Laval University in Canada in a report in the current issue of Circulation (Circulation. 2003;108:983–988OpenUrl).
The researchers estimated the indexed valve effective orifice area for each type and size of prosthesis implanted in 1266 consecutive patients. They defined the prosthesis-patient mismatch as not clinically significant if the measurement was greater than 0.85 cm2/m2, moderate if greater than 0.65 cm2/m2 and less than 0.85 cm2/m2, and severe if less than 0.65 cm2/m2.
Thirty-eight percent of patients had moderate to severe prosthesis-patient mismatch. Fifty-eight of the 1266 patients died within 30 days of the implantation. The strongest independent predictors of death were left ventricular ejection fraction of less than 40%, infectious endocarditis, an emergency or salvage operation, and being on the cardiopulmonary bypass machine for longer than 2 hours. The relative risk was increased 2.1-fold in patients with moderate prosthesis-patient mismatch and 11.4-fold in those with severe prosthesis-patient mismatch. The risk of mortality was even higher when patients had prosthesis-patient mismatch and an ejection fraction of less than 40%.
The researchers noted that “in contrast to other risk factors, moderate to severe PPM [patient-prosthesis mismatch] can be largely avoided with the use of a prospective strategy at the time of the operation.”
Taking Time for Angioplasty
Setting up systems to transfer patients who have suffered myocardial infarction with ST-segment elevation to centers where primary angioplasty can be performed saves lives when travel time is less than 2 hours, said Danish researchers in the August 21, 2003, issue of The New England Journal of Medicine (N Engl J Med. 2003;349:733–743OpenUrlCrossRefPubMed).
Researchers involved in the Danish Multicenter Randomized Study on Fibrinolytic Therapy versus Acute Coronary Angioplasty in Acute Myocardial Infarction (DANAMI-2) randomly assigned 1572 patients with acute myocardial infarction to angioplasty or accelerated treatment with alteplase. A total of 1129 patients were enrolled in community or referral hospitals, and 443 patients were enrolled at 5 centers capable of providing invasive treatment.
Of the patients who underwent randomization in community hospitals, 8.5% of patients who received angioplasty suffered one of the primary end points of death, reinfarction, or disabling stroke within 30 days. In the group that underwent fibrinolysis, 14.2% suffered one of the end point conditions. Similar results were seen in patients enrolled at the invasive treatment centers.
Patients had a better outcome after angioplasty because they were less likely to have another infarction in the short term, the researchers said. The death and stroke rates were not significantly different. The DANAMI-2 research noted that 96% of subjects were transferred to angioplasty centers within 2 hours. They concluded that establishing a strategy to provide angioplasty in a center set up to perform it was superior to providing fibrinolysis in a community hospital as long as transfer time is no longer than 120 minutes.
In an accompanying editorial, Alice K. Jacobs, MD, of Boston University Medical Center (N Engl J Med. 2003;349:798–800), wrote that of 5 randomized trials that have attempted to address the issue of whether fibrinolytic therapy or primary angioplasty is best, DANAMI-2 is “noteworthy for its randomized design, its practical approach to a critical question, and its careful consideration of the time between the onset of symptoms (in addition to arrival at the hospital) and reperfusion in its comparisons of strategies and treatment centers. Of note, 96% of the patients were transferred from the referral hospital to an angioplasty center within 2 hours after randomization. In fact, an analysis of all 5 trials that compared transfer for primary percutaneous coronary intervention with on-site fibrinolytic therapy revealed that despite the delay necessary for the transfer (43 minutes on average), primary percutaneous coronary intervention was associated with significant reductions in the rates of death, nonfatal reinfarction, and total stroke.”
The key to improved survival is clearly primary angioplasty in the hands of experienced physicians who practice at centers set up to perform primary angioplasty, she wrote. It must, however, be accompanied by the means to transport patients to those hospitals quickly and continued efforts to minimize the wait times.
That Fatal Risk Factor
Even though the common perception is that many people without risk factors for heart disease have heart attacks or die from coronary heart disease, that’s not true, said researchers led by Philip Greenland, MD, of the Feinberg School of Medicine at Northwestern University in Chicago. According to a meta-analysis of 3 major studies, almost all such heart disease victims have at least 1 of 4 major risk factors (cigarette smoking, high cholesterol, high blood pressure, or diabetes), they wrote in the August 20, 2003, issue of The Journal of the American Medical Association (JAMA. 2003;290:891–897OpenUrlCrossRefPubMed).
The 3 groups of patients studied were (1) subjects from the Chicago Heart Association Detection Project in Industry, with a population sample of 35 642 employed men and women aged 18 to 59 years; (2) screenees for the Multiple Risk Factor Intervention Trial, including 347 978 men aged 35 to 57 years; and (3) a population-based sample of 3295 men and women aged 34 to 59 years from the Framingham Heart Study. Among those who suffered a fatal event, the researchers found evidence of at least one major risk factor in 87% to 100%. Among those who had nonfatal events, one risk factor was found in 92% of men and 87% of women, all aged 40 to 59 years.
A similar study led by Umesh M. Khot, MD, of Indiana Heart Physicians in Indianapolis evaluated 14 studies and came to similar conclusions (JAMA. 2003;290:898–904OpenUrlCrossRefPubMed). He and his colleagues wrote: “It is increasingly clear that the 4 conventional risk factors and their resulting health risks are largely preventable by a healthy lifestyle. The continued emphasis on patients lacking conventional risk factors, a situation that we have shown occurs only in a small minority of patients with CHD [coronary heart disease], fails to acknowledge the important insights that have been made in current understanding of the relationships among lifestyle, conventional risk factors, and CHD. These insights indicate that intense focus on the 4 conventional risk factors and the lifestyle behaviors causing them has great potential to decrease the worldwide epidemic of CHD.”