Rate of progression and functional significance of aortic root calcification after homograft versus freestyle aortic root replacement.

BACKGROUND: Calcification is an important limitation after aortic root replacement. The aims were to compare the long-term degree and rate of calcification of homografts versus Medtronic freestyle aortic roots to determine the functional consequences and predictive factors. METHODS AND RESULTS: One hundred sixty-six patients were prospectively randomized to undergo homograft versus freestyle total aortic root replacement. Of those, 98 patients underwent a total of 248 electron beam computed tomography studies at 0.5, 1, 1.5, 2, 3, and 8 years. All patients underwent yearly clinical and echocardiographic follow-up. Calcium scores were measured using Agatston scoring. Mixed effects models demonstrate significantly higher calcium scores in homograft roots than freestyle at 1.5 years (P=0.02), 2 years (P=0.02), and 3 years (P=0.01), with a trend at 1 year (P=0.06) and 8 years (P=0.1). Homograft calcification occurs significantly faster than in freestyle prostheses between 6 months and 3 years after surgery (P=0.02). Calcification occurs at a similar rate thereafter up to 8 years (P=0.3). At 8 years, freedom from aortic valve dysfunction was lower in homografts than freestyle roots (P=0.06). Freedom from reoperation was 93+/-4% in the homograft group versus 100+/-0% in the freestyle group at 8 years (P=0.01). On multivariate analysis, redo surgery (P<0.001), smoking (P<0.01), atrial fibrillation (P=0.001), family history of coronary artery disease (P<0.01), and a degenerative etiology (P=0.02) were predictive of higher calcium scores. CONCLUSIONS: Homograft roots exhibit significantly higher calcium scores than freestyle roots because of faster early calcification.

A rare case of anomalous origin of the left main coronary artery in an adult patient.

Anomalous origin of left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly that causes a left-to-right shunt via the coronary system, resulting in coronary steal. We report an unusual case of a healthy 48 years-old patient presenting with dyspnea on exertion and mild chest pain who underwent surgical correction of this rare anomaly. Multiple procedures have been proposed in adults with ALCAPA. Although re-implantation of the left main coronary artery (LMCA) to the aorta remains the most physiological correction for this anomaly, the combination of LMCA ligation and coronary artery bypass grafting provides a dual coronary flow system and is preferable when re-implantation is impossible.

Late outcomes following freestyle versus homograft aortic root replacement: results from a prospective randomized trial.

OBJECTIVES: The aims of this study were to compare long-term results after homograft versus Freestyle (Medtronic Inc., Minneapolis, Minnesota) aortic root replacement. BACKGROUND: The ideal substitute for aortic root replacement remains undetermined. METHODS: Between 1997 and 2005, 166 patients (age 65 +/- 8 years) undergoing total aortic root replacement were randomized to receive a homograft (n = 76) or a Freestyle bioprosthesis (n = 90). Six patients randomly assigned to homograft crossed over to Freestyle because of unavailability of suitably sized homografts. Median follow-up was 7.6 years (maximum 11 years; 1,035 patient-years). "Evolving" aortic valve dysfunction was defined as aortic regurgitation >/=2/4 and/or peak gradient >20 mm Hg. RESULTS: Patient characteristics were comparable between groups. Concomitant procedures were performed in 44% and 47% of Freestyle and homograft patients, respectively (p = 0.5). Overall hospital mortality was 4.8% (1% for isolated root replacement). Eight-year survival was 80 +/- 5% in the Freestyle group versus 77 +/- 6% in the homograft group (p = 0.9). Freedom from need for reoperation at 8 years was significantly higher after Freestyle root replacement (100 +/- 0% vs. 90 +/- 5% after homograft replacement; p = 0.02). All reoperations were secondary to structural valve deterioration (n = 6). At last echocardiographic follow-up, actuarial freedom from evolving aortic valve dysfunction was 86 +/- 5% for Freestyle bioprostheses versus 37 +/- 7% for homografts (p < 0.001). Clinically, freedom from New York Heart Association functional class III to IV and freedom from valve-related complications were similar between groups (p = 0.7 and p = 0.9, respectively). CONCLUSIONS: In this patient group, late survival is similar after homograft versus Freestyle root replacement. However, Freestyle aortic root replacement is associated with significantly less progressive aortic valve dysfunction and a lower need for reoperations.

Endothelium-dependent regulation of the mechanical properties of aortic valve cusps.

OBJECTIVES: The aim of this study was to evaluate the role of valve endothelium in regulating the mechanical properties of aortic valve cusps. BACKGROUND: Mechanical properties of valve cusps are key to their function and durability; however, little is known about the regulation of valve biomechanics. METHODS: Mechanical properties of porcine aortic valve leaflets were evaluated in response to serotonin (5-hydroxytryptamine [5-HT]), with and without N-nitro-L-arginine-methyl-ester (L-NAME) or endothelial denudation, and endothelin (ET)-1, with and without cytochalasin-B. RESULTS: Under physiological loading conditions, 5-HT induced a decrease in the areal stiffness of the cusp (-25.0 +/- 4.0%; p < 0.01 vs. control), which was reversed by L-NAME or endothelial denudation (+17.5 +/- 5.3%, p = 0.07, and +14.7 +/- 1.8%, p < 0.05 vs. control, respectively). ET-1 caused an increase in stiffness (+34.4 +/- 13.8%; p < 0.05 vs. control), but not in the presence of cytochalasin-B (p = 0.29 vs. control). Changes in cusp stiffness were accompanied by aortic cusp relaxations to 5-HT (-0.29% +/- 0.1% change in load per 10-fold increase in 5-HT concentration; p = 0.03), which were reversed by endothelial denudation (+0.29 +/- 0.06% change in load per 10-fold increase in 5-HT concentration; p = 0.02) and by L-NAME (p < 0.05). Valve cusps contracted in response to ET-1 (+0.29 +/- 0.08% change in load per 10-fold increase in ET-1 concentration; p = 0.02), which was inhibited by cytochalasin-B. CONCLUSIONS: These data highlight the role of the endothelium in regulating the mechanical properties of aortic valve cusps and underline the importance of valve cellular integrity for optimal valve function.