BOCA RATON, FLA. – Beta-blocker therapy and strict, lifelong control of hypertension are key to avoiding late reoperation after repair of acute type A aortic dissection, according to a large, 25-year, single-center follow-up study.
Operative mortality was 16% among 252 patients who underwent repair of acute type A aortic dissection at the hands of 26 surgeons at Barnes-Jewish Hospital in St. Louis during 1984-2009. Of 28 variables that were scrutinized in a multivariate analysis, only one proved to be an independent risk factor for operative mortality: branch vessel malperfusion at presentation, with an associated 2.5-fold increased risk, Dr. Spencer J. Melby reported at the annual meeting of the American Surgical Association.
Some 27 of 211 operative survivors required 30 late reoperations. Four variables were independently predictive of late reoperation: male sex, Marfan syndrome, not being on a beta-blocker at last follow-up, and systolic blood pressure (SBP) greater than 120 mm Hg, according to Dr. Melby of Washington University in St. Louis.
The rates of freedom from reoperation among patients on beta-blocker therapy at 10 and 15 years were 86% and 83%, respectively, compared with 57% and 37% in patients who were not on the medication.
Patients who maintained their SBP below 120 mm Hg had 10- and 15-year rates of freedom from reoperation of 92%. Among those whose SBP was 120-140 mm Hg, the rates were 74% and 66%. In patients who maintained SBP in excess of 140 mm Hg, the 10- and 15-year rates of freedom from reoperation was 49% and 30%.
In terms of perfusion techniques that were utilized in the initial repair, 35% of patients were placed on an aortic cross-clamp only, 30% had hypothermic cardiac arrest with retrograde cerebral perfusion, and 35% got hypothermic cardiac arrest without retrograde cerebral perfusion.
Importantly, long-term survival was not related to operative approach. Late survival was decreased, however, in patients with previous stroke or chronic renal insufficiency.
Discussant Dr. Thoralf M. Sundt III noted that although acute aortic dissection is an uncommon condition, it is nonetheless the most common fatal catastrophe of the aorta. Multiple studies over the years indicate that not much progress has been made in improving the high perioperative and long-term morbidity and mortality.
"We don’t seem to be learning very much over time. It’s not getting better. So a study such as this one that can impact the long-term results in these patients is important," said Dr. Sundt, chief of cardiac surgery at Massachusetts General Hospital, Boston.
He particularly welcomed Dr. Melby’s emphasis on lifelong beta-blocker therapy.
"It may seem a bit odd for surgeons to be focusing on pharmacologic treatment, but in fact aortic disease is really a disease that’s most often treated by surgeons. There are few medical vascular specialists, and so it really is important for us to follow these patients. This is a chronic condition, and we ought to adopt a posture towards that condition where we are responsible for caring for these patients over time," according to the surgeon.
Dr. Sundt noted that many surgeons have adopted as dogma that these repairs should be done under hypothermic circulatory arrest rather than cross-clamp. "Your group is bucking the trend," he commented.
Dr. Melby agreed that hypothermic cardiac arrest is "trendy." Some surgeons at Barnes-Jewish use it routinely. But in the study, the risk of reoperation for bleeding was 17% in patients who were managed via hypothermic cardiac arrest, compared with 7% with cross-clamp. Cardiopulmonary bypass time was about 30 minutes shorter with the cross-clamp.
"One of the conclusions of our paper is that because we found [that] long-term outcomes were independent of the technique, it’s safe to say that surgeons should treat this problem in the way they’re most comfortable," he added.
Dr. Melby said that he has no relevant financial interests.