Continuous assessment of carotid intima-media thickness applied to estimate a volumetric compliance using B-mode ultrasound sequences.

Recent reports have shown that the carotid artery wall had significant movements not only in the radial but also in the longitudinal direction during the cardiac cycle. Accordingly, the idea that longitudinal elongations could be systematically neglected for compliance estimations became controversial. Assuming a dynamic change in vessel length, the standard measurement of cross-sectional compliance can be revised. In this work, we propose to estimate a volumetric compliance based on continuous measurements of carotid diameter and intima-media thickness (IMT) from B-mode ultrasound sequences. Assuming the principle of conservation of the mass of wall volume (compressibility equals zero), a temporal longitudinal elongation can be calculated to estimate a volumetric compliance. Moreover, elongations can also be estimated allowing small compressibility factors to model some wall leakage. The cross-sectional and the volumetric compliance were estimated in 45 healthy volunteers and 19 asymptomatic patients. The standard measurement underestimated the volumetric compliance by 25% for young volunteers (p < 0.01) and 17% for patients (p < 0.05). When compressibility factors different from zero were allowed, volunteers and patients reached values of 9% and 4%, respectively. We conclude that a simultaneous assessment of carotid diameter and IMT can be employed to estimate a volumetric compliance incorporating a longitudinal elongation. The cross-sectional compliance, that neglects the change in vessel length, underestimates the volumetric compliance.

Off-pump coronary operation at the Favaloro Foundation: results in 264 patients.

BACKGROUND: Our objective was to determine whether complete myocardial revascularization "off pump" was feasible while maintaining the efficacy of conventional surgical techniques. METHODS: 264 patients were operated on between March 15, 1998, and August 26, 1999. A total of 218 (82.6%) were men and the average age was 61.4 years (range 28 to 87 years). Left main occlusions were present in 10.2% and 84% had multiple vessel disease. A total of 628 grafts were implanted, an average of 2.4 grafts per patient. Total arterial revascularization was achieved in 81.5% using both internal mammary arteries and the radial artery, one or more venous grafts in 18.1%, and venous alone in 0.3%. RESULTS: Surgical mortality was 2.2% and perioperative myocardial infarction was 3%. There were no neurologic events in this group of patients. In the first 73 patients coronary angiography control was performed before discharge and all grafts were patent. Angioplasty was carried out in 2 patients (0.76%) and conversion of procedure in 4 (1.5%). Follow-up time was 4 to 14 months. CONCLUSIONS: This procedure enabled revascularization of all areas of the heart, usually with total arterial revascularization, and excellent patency rates. The morbidity and mortality observed was similar to conventional surgery. The incidence of secondary complications (bleeding, need for transfusion, prolonged mechanical ventilation, or neurologic events) was lower.