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Vulnerable plaque generally contains a thin fibrous cap, lipid pools, and reduced internal plaque collagen. Arterial fluorescence analysis can differentiate atherosclerotic lesions from normal arteries; however, the contribution of the lipid core to atherosclerotic arterial fluorescence remains controversial. This study aimed to identify lipid core fluorophores and to differentiate the lipid core from normal artery and atheroma. The helium-cadmium laser-induced fluorescence spectra of cadaveric arteries and known chemical constituents were recorded. Lipid core fluorescence spectra exhibited marked red shifts and broadening compared with the fluorescence spectra of normal tissue and atheroma. Similar fluorescence spectra were obtained for lipid core and oxidized low density lipoprotein, for atheroma and collagen, and for normal artery and elastin. A classification based on collagen, elastin, and oxidized low density lipoprotein spectral decomposition could discriminate the lipid core (n=29), normal artery (n=74), atheroma (n=73), and preatheroma (n=10) with 86% accuracy. Fibrous cap thickness was correlated with the spectral collagen content index (r=0.65, P<0.0001), especially at a thickness of <200 microm. We conclude that a classification algorithm based on chemical spectral decomposition can accurately classify the fluorescence spectra of normal artery, atheroma, and lipid core and may be useful in identifying vulnerable atheroma in vivo.

In administrative databases the International Classification of Diseases, Version 9, Clinical Modification (ICD-9-CM) is often used to identify patients with specific diagnoses. However, certain conditions may not be accurately reflected by the ICD-9 codes. We assessed the accuracy of ICD-9 coding for cerebrovascular disease by comparing ICD-9 codes in an administrative database with clinical findings ascertained from medical record abstractions. We selected patients with ICD-9 diagnostic codes of 433 through 436 (in either the primary or secondary positions) from an administrative database of patients hospitalized in five academic medical centers in 1992. Medical records of the selected patients were reviewed by trained medical abstractors, and the patients' clinical conditions during the admission (stroke, TIA, asymptomatic) were recorded, as well as any history of cerebrovascular symptoms. Results of the medical record review were compared with the ICD-9 codes from the administrative database. More than 85% of those patients with the ICD-9 code 433 were asymptomatic for the index admission. More than one-third of these asymptomatic patients did not undergo either cerebral angiography or carotid endarterectomy. For ICD-9 code 434, 85% of patients were classified as having a stroke and for ICD-9 code 435, 77% had TIAs. For code 436, 77% of patients were classified as having strokes. Limiting the identifying ICD-9 code to the primary position increased the likelihood of agreement with the medical record review. The ICD-9 coding scheme may be inaccurate in the classification of patients with ischemic cerebrovascular disease. Its limitations must be recognized in the analyses of administrative databases selected by using ICD-9 codes 433 through 436.

A survey of studies was used to investigate the economic repercussions of arterial disease; these repercussions included the cost of the disease and its management, and cost/efficacy, cost/utility, and cost/benefit studies of preventive, diagnostic, and therapeutic strategies. The study presented is an evaluation of the socio-economic consequences of peripheral occlusive arterial disease of the lower limbs (POADLL). The cost of health care was measured by means of a prospective 6-month study of 85 patients recruited in 6 centers. The average cost over the 6-month period was 15,735 FF (1991 francs) ($2,760 U.S.). The 85 patients were classified by age, sex, risk factors, concomitant disease, and how the illness was managed, notably in terms of hospitalization and vascular surgery. The four-group classification was used to calculate an annual management cost for POADLL, which ranged from 9,500 FF ($1,667 U.S.) for a stage II patient (mean age, 66 years) with no major risk factors and not presenting any complication requiring admission to hospital, to 35,000 FF ($6,140 U.S.) for patients (mean age, 62 years) who presented major risk factors and who required vascular surgery during the year.

A minicomputer based pattern recognition method has been used to prospectively classify the category of disease involvement of 105 carotid arteries. The system utilized spectral patterns obtained from a combined B-mode/pulsed Doppler unit. All decisions are based upon comparison of an unknown, averaged waveform with a series of vessels with known severity of disease. The variability in the computer decision as compared to arteriography is discussed.