Physician concludes that vascular ultrasound screening identifies heart disease risk
among women with greater accuracy
Findings presented at World Congress of Cardiology
Barcelona, September 3, 2006 - Sonosite, Inc. (Nasdaq: SONO), the world leader in hand-carried ultrasound, announced today that Dr. John Postley of the New York Physicians Group has presented results from his study demonstrating that vascular ultrasound screening can be a more accurate means of risk stratification for heart attack, particularly among women, than the Framingham Risk Score, which has been the traditional method of identifying cardiovascular risk. Dr. Postley presented his study, "Gender Differences in the Relationship of Ultrasound Identified Atherosclerosis to Framingham Risk Score," on Sunday, September 3 at the World Congress of Cardiology 2006. (The Congress is meeting at the Fira Gran Mia M2 in Barcelona until September 6.)
Dr. Postley used Sonosite hand-carried ultrasound systems in his study, in which 120 patients from his practice were examined with ultrasound for the presence of carotid and femoral arterial plaque and the measurement of carotid intimal medial thickness (CIMT). Among the 50 women in the study, Dr. Postley found no correlation between Framingham Risk Scoring (FRS) and the thickening of the endothelial lining of the carotid artery, or CIMT, a well established surrogate for cardiovascular disease events. Further, while 72 percent of these women were at low risk for heart attack according to FRS, 50 percent of this group had incidence of plaque. Even in the absence of other risk factors, presence of plaque is a proven precursor to heart attack and stroke.
Dr. Postley's poster can be viewed on Sonosite's website by clicking here. "Atherosclerosis, as it ultimately leads to heart attack and stroke, is the leading cause of death in the United States and the mortality rate associated with the first heart attack or stroke is very high," said Dr. Postley. "Clearly, a better method for risk-stratifying patients is needed so that preventive treatment can begin for those who need it most. Screening for CIMT and plaque with vascular ultrasound can uncover at-risk patients with greater accuracy than traditional methods, and should allow for earlier intervention to prevent the progression of disease. "CIMT and plaque screening should be performed during the annual physical examination, and hand-carried ultrasound is the ideal screening tool," added Dr. Postley. "With a resolution limit of one-tenth of a millimeter, ultrasound can detect early thickening of the intimal medial layer that would be overlooked by CT or MR angiography. If primary care ultrasound was more commonly used in the physical exam, I believe it could save hundreds of thousands of lives every year" "This is groundbreaking research," said Kevin M. Goodwin, President and CEO of Sonosite. "And it underscores our belief that CIMT measurement belongs in the physical exam, and that vascular imaging by primary care physicians can enhance the life saving potential of a routine doctor's visit.
Dr. Postley's study should improve the early detection and treatment of atherosclerosis and we are delighted that our systems played such an important role." All CIMT measurements were made with a Sonosite TITAN system and patented SonoCalc IMT automated edge detection software. SonoCalc IMT results can be used adjunctively with other medical data by a physician to help assess the cardiovascular health of a patient. Dr. Postley is a member of Sonosite's IMT Advisory Board, a group of primary care physicians, cardiologists and neurologists evaluating carotid IMT, to enhance the physical examination and to more effectively identify and manage patients at risk for cardiovascular disease.
Atherosclerosis as manifest in coronary artery disease, cerebrovascular disease and peripheral vascular disease is the leading cause of death in the United States. Mortality of first events, particularly with myocardial infarction, is very high and it is urgent that we have a method of identifying people at risk before that initial event. The use of Common carotid intimal medial thickness (CIMT) is well established as a surrogate for cardiovascular disease events. The use of screening vascular ultrasound of the carotid and femoral arteries as a surrogate of coronary atherosclerosis has been validated by the CAFES-CAVE study. Framingham Risk Score (FRS) has been the traditional method of identifying cardiovascular risk.
In the present study, 120 untreated and unselected patients drawn from a university based group medical practice were evaluated by ultrasound for the presence and type of carotid and femoral arterial bifurcation plaque and the measurement of common carotid intimal medial thickness (CIMT). The age range was 34 to 74 years and there were 50 women and 70 men evaluated. Distribution of FRS was among men: 0-6, 31%; 7-12, 39%; 13-25, 30% while among women: 0-6, 72% and 7-18, 28%.
The correlation of FRS with Average CIMT was r= 0.40 (p<0.001) for all patients and the correlation of FRS with Maximum CIMT was r=0.40 (p<0.001). When CIMT measurements were divided by gender, correlation of FRS with Average mean CIMT (r=0.49) and Maximum CIMT (r=0.47) was highly significant (p<0.001) among men while there was no correlation for Average CIMT (r=0.04, p=0.7) or for Maximum CIMT (r=0.07, p=0.6) among women. This gender based divergence of the correlation of CIMT with FRS was repeated in the assessment of arterial plaque. Among men, the incidence of any plaque for each FRS group was: 0-6, 27%; 7-12, 59%; 13-25, 67% while among women: 0-6, 50% and 7-18, 43%. Screening vascular ultrasound analysis produces a different pattern of risk assessment than does traditional Framingham risk analysis particularly in women. The use of screening vascular ultrasound as a complement to traditional risk analysis can uncover additional patients at risk and allow earlier intervention to prevent disease progression.
Sonosite, Inc. (www.sonosite.com) is the innovator and world leader in hand-carried ultrasound, with an installed base of more than 25,000 systems. The company, headquartered near Seattle, is represented by eight subsidiaries and a global distribution network in over 75 countries. Sonosite's small, lightweight systems are expanding the use of ultrasound across the clinical spectrum by cost-effectively bringing high performance ultrasound to the point of patient care. The company employs approximately 500 people worldwide.