Faculty Bibliography

The model of surgery first and always for Type A aortic dissections has continued to evolve. During the last three decades, various studies have demonstrated that in select patients, surgery should be delayed or avoided. This case series examines three cases in which patients were medically treated. Furthermore, we review the literature and when surgery should be delayed for acute Type A aortic dissections.

BACKGROUND:The role of three-dimensional transesophageal echocardiography (3DTEE) vs multidetector computed tomography (MDCT) in aortic annular sizing has been poorly defined in patients undergoing transcatheter aortic valve replacements (TAVR). We set to determine the correlation between 3DTEE and MDCT in measuring the aortic annulus prior to TAVR. METHODS:In an observational, retrospective study, we compared aortic annular areas measured by MDCT and 3DTEE in TAVR patients. The aortic annular area was measured by planimetry of images obtained by MDCT pre-TAVR and by intra-TAVR TEE using 3D rendering of the aortic annulus followed by planimetry. Our primary outcome was degree of correlation between mean aortic annulus area by 3DTEE and MDCT. RESULTS:. There was a strong positive linear correlation between aortic annular area measurements obtained from these two modalities with mild relative underestimation by 3DTEE (ρ=.833). This relationship can be estimated using the predictive formula: [Formula: see text] CONCLUSIONS: Three-dimensional transesophageal echocardiography measurements have a high degree of correlation with MDCT measurements and thus can assist in proper valve prosthesis selection for TAVR. Our study thus supports use of 3DTEE as a reasonable alternative imaging modality in patients undergoing TAVR.

OBJECTIVES/OBJECTIVE:To review the current general concepts and understanding of the natural history of thoracic aortic aneurysm and their clinical implications. METHODS:Data on the the normal thoracic aortas were derived from the database of the Multi-Ethnic Study of Atherosclerosis (n = 3573), representative of the general population. Data on diseased thoracic aorta were derived from the database of the Aortic Institute at Yale-New Haven Hospital (n = 3263), representative of patients with thoracic aortic aneurysm and dissection. RESULTS:Our studies have shown that the normal aorta in the general population is small (3.2 cm for the ascending aorta). Aortas larger than 5 cm are rare in the real world. The aneurysmal aorta grows at a mean of 0.2 cm/y, and larger aneurysms grow faster than do smaller ones. The dissection size paradox (which shows some aortic dissections occurring at small aneurysm sizes) is explained by the huge number of patients with small aortas in the general population. Genetic testing of patients with thoracic aortic disease helps identify genes responsible for aortic aneurysm and dissection. New imaging techniques such as 4-dimensional magnetic resonance imaging may add engineering data to our decision making. CONCLUSIONS:Size continues to be a strong predictor of natural complications and a suitable parameter for intervention. As we enter the era of personalized aneurysm care, it is likely that specific genetic mutations will facilitate the determination of the appropriate size criterion for surgical intervention in individual cases.

BACKGROUND:Current guidelines recommend a diameter of 5-5.5 cm as the threshold for surgery on the ascending aorta. However, a study from the International Registry of Acute Aortic Dissection showed that nearly 60% occurred at <5.5 cm (the 'aortic size paradox')--leading to a debate whether the size threshold should be lowered. However, the study showing dissection at small size had no knowledge of the population at risk. Herein, we aim to calculate the relative risk of aortic dissection at sizes<5.5 cm by analyzing both the number of occurring dissections (numerator) and the population at risk at each aortic size (denominator). METHODS:Using a publicly available database of 3,573 multiethnic subjects (46% male, mean age 60.7 years) from the general population, we plotted a distribution curve of ascending aortic size (by magnetic resonance imaging). The relative risk of aortic dissection was calculated by dividing the proportion of dissections occurring at each size (numerator) by the proportion of aortas of that same size in the general population (denominator). RESULTS:The mean ascending aortic diameter of the reference population was 3.2 cm (±0.4 cm). The largest diameter was 4.9 cm in women and 5.0 cm in men. The proportion of subjects with an aorta <3.5 cm was 79.2%, that of subjects with 3.5-3.9 cm was 18.0%, that of subjects with 4.0-4.4 cm was 2.6%, and that of subjects with ≥4.5 cm was 0.22%. The relative risk of dissection in those categories was found to be 0.055, 2.5, 4.9, and 346.8, respectively. Patients with an aorta≥4.5 cm were 6,305 times more likely to suffer aortic dissection than those with an aorta<3.5 cm. CONCLUSIONS:The normal aorta is deceptively small, most commonly <3.5 cm. The aortic size paradox is a byproduct of the very large number of patients in small size ranges. This study fully supports current recommendations for surgical intervention at 5-5.5 cm.