ADULT CARDIAC
94
RYLSKI ET AL CHRONIC TYPE A AORTIC DISSECTION
Ann Thorac Surg 2015;99:88–94
INVITED COMMENTARY Since the seminal article published by Hirst and colleagues in 1958 [1], the mortality associated with acute type A aortic dissection has remained astoundingly high: 75% of patients expire within 2 weeks without undergoing an operation. However, information on the fortunate few who survive the initial event is very limited. The data presented in this article are quite valuable because they outline a spectrum of presentation, predisposing conditions, surgical outcomes, and long-term survival for patients with a chronic type A dissection [2]. Amazingly, but consistent with what most of us have witnessed, a majority of patients were found to have a chronic dissection by serendipity. Few had symptoms related to the dissection, and a majority could not recall an event that one might ascribe to a dissecting aorta. Although the aortas in the cohort with chronic dissections were generally larger, with more severe aortic valve insufficiency and with worse left ventricular function than their counterparts with acute dissections, it was quite rare for a patient to present with either rupture or malperfusion and in need of an emergent operation. This more elective presentation, and the time it allowed for more thorough preoperative evaluation and normalization of end organ function, was a major contributor to the threefold reduction in perioperative mortality seen when operations were performed beyond the acute phase. These patients were also fortunate in that the dissection extended beyond the arch less than one-third of the time. This not only made the surgical procedure less complicated but also improved long-term survival by eliminating the need for a high-risk downstream operation on the dissected thoracoabdominal aorta. Two additional pieces of information extracted from these data are worthy of further discussion. First, acute type A intramural hematoma does not appear to be a benign disease. Six patients with an intramural hematoma were followed up after the acute event. Although none experienced a rupture or an adverse event during a
Ó 2015 by The Society of Thoracic Surgeons Published by Elsevier
period of observation, all went on to need operations for aortic expansion, conversion to classic dissection, or experience ongoing symptoms. It may be more logical to proceed with surgery at the time of presentation and eliminate the potential risk one might incur by waiting for the inevitable need for an operation. The second issue surrounds the indications for an operation. The authors suggest a diameter of 5.5 cm or more as an indication to proceed with repair. Although this may be reasonable in patients with advanced comorbidities or mediastinal scarring after previous heart operations, it seems counterintuitive that any chronic type A dissection should be followed irrespective of diameter. Perhaps data will surface describing a similar cohort of patients with small aortic diameters who were safely followed with serial imaging. However, given the relatively low perioperative risk and excellent long-term survival experienced by these patients, it seems more reasonable to support a more aggressive surgical approach in any patient found to have a chronic type A dissection. Leonard N. Girardi, MD Department of Cardiothoracic Surgery Weill Cornell Medical College 525 East 68th St, M-404 New York, NY 10021 e-mail: [email protected]
References 1. Hirst AE Jr, Johns VJ Jr, Kime SW Jr. Dissecting aneurysm of the aorta: a review of 505 cases. Medicine (Baltimore) 1958;37: 217–79. 2. Rylski B, Milewski RK, Bavaria JE, Branchetti E, Vallabhajosyula P, Szeto WY, Desai ND. Outcomes of surgery for chronic type A aortic dissection. Ann Thorac Surg 2015;99: 88–94.
0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2014.08.007
94
RYLSKI ET AL CHRONIC TYPE A AORTIC DISSECTION
Ann Thorac Surg 2015;99:88–94
INVITED COMMENTARY Since the seminal article published by Hirst and colleagues in 1958 [1], the mortality associated with acute type A aortic dissection has remained astoundingly high: 75% of patients expire within 2 weeks without undergoing an operation. However, information on the fortunate few who survive the initial event is very limited. The data presented in this article are quite valuable because they outline a spectrum of presentation, predisposing conditions, surgical outcomes, and long-term survival for patients with a chronic type A dissection [2]. Amazingly, but consistent with what most of us have witnessed, a majority of patients were found to have a chronic dissection by serendipity. Few had symptoms related to the dissection, and a majority could not recall an event that one might ascribe to a dissecting aorta. Although the aortas in the cohort with chronic dissections were generally larger, with more severe aortic valve insufficiency and with worse left ventricular function than their counterparts with acute dissections, it was quite rare for a patient to present with either rupture or malperfusion and in need of an emergent operation. This more elective presentation, and the time it allowed for more thorough preoperative evaluation and normalization of end organ function, was a major contributor to the threefold reduction in perioperative mortality seen when operations were performed beyond the acute phase. These patients were also fortunate in that the dissection extended beyond the arch less than one-third of the time. This not only made the surgical procedure less complicated but also improved long-term survival by eliminating the need for a high-risk downstream operation on the dissected thoracoabdominal aorta. Two additional pieces of information extracted from these data are worthy of further discussion. First, acute type A intramural hematoma does not appear to be a benign disease. Six patients with an intramural hematoma were followed up after the acute event. Although none experienced a rupture or an adverse event during a
Ó 2015 by The Society of Thoracic Surgeons Published by Elsevier
period of observation, all went on to need operations for aortic expansion, conversion to classic dissection, or experience ongoing symptoms. It may be more logical to proceed with surgery at the time of presentation and eliminate the potential risk one might incur by waiting for the inevitable need for an operation. The second issue surrounds the indications for an operation. The authors suggest a diameter of 5.5 cm or more as an indication to proceed with repair. Although this may be reasonable in patients with advanced comorbidities or mediastinal scarring after previous heart operations, it seems counterintuitive that any chronic type A dissection should be followed irrespective of diameter. Perhaps data will surface describing a similar cohort of patients with small aortic diameters who were safely followed with serial imaging. However, given the relatively low perioperative risk and excellent long-term survival experienced by these patients, it seems more reasonable to support a more aggressive surgical approach in any patient found to have a chronic type A dissection. Leonard N. Girardi, MD Department of Cardiothoracic Surgery Weill Cornell Medical College 525 East 68th St, M-404 New York, NY 10021 e-mail: [email protected]
References 1. Hirst AE Jr, Johns VJ Jr, Kime SW Jr. Dissecting aneurysm of the aorta: a review of 505 cases. Medicine (Baltimore) 1958;37: 217–79. 2. Rylski B, Milewski RK, Bavaria JE, Branchetti E, Vallabhajosyula P, Szeto WY, Desai ND. Outcomes of surgery for chronic type A aortic dissection. Ann Thorac Surg 2015;99: 88–94.
0003-4975/$36.00 http://dx.doi.org/10.1016/j.athoracsur.2014.08.007
