Aortic Dissection Becoming Less Deadly

Published: Oct 22, 2014

By Crystal Phend, Senior Staff Writer, MedPage Today

Aortic dissection survival has improved, particularly for patients getting surgical repair, a Medicare analysis showed.

Overall 30-day mortality rates fell from 31.8% to 25.4% from 2000 to 2011, while 1-year death rates declined from 42.6% to 37.4%, Harlan M. Krumholz, MD, of Yale, and colleagues found.

Those significant changes in the Inpatient Medicare data came against a backdrop of no change in the hospitalization rate for aortic dissection, which remained at 10 per 100,000 person-years.

The drop in mortality was greatest among patients getting surgical repair of type A dissections (from 30.7% to 21.4% at 30 days and from 39.9% to 31.6% at 1 year), they reported in the November issue ofCirculation: Cardiovascular Quality and Outcomes.

For surgical repair of type B dissections, the decrease was more modest, from 24.9% to 21.0% at 30 days and from 36.4% to 32.5% at 1 year.

Mortality with medical management also showed a slight decline over the 2000 to 2011 study period, from 32.8% to 28.9% at 30 days and from 44.0% to 41.6% at 1-year.

"In contrast, among the limited number of patients who underwent TEVAR [thoracic endovascular aortic repair], 30-day mortality changed from 9.5% in 2005 to 13.9% in year 2011 (P=0.4 for trend) and 1-year mortality changed from 16.7% in 2005 to 25.8% in year 2011 (P=0.3 for trend), respectively," the researchers noted.

That apparent increase in mortality after introduction of the technique did not meet statistical significance, though, they cautioned.

The study included all 79.3 million Medicare fee-for-service beneficiaries from 2000 through 2011.

The 32,057 initial aortic dissection hospitalizations in that population over the study period were followed for mortality outcome through vital status files.

Adjustment for age, sex, race, and comorbidities left the results largely unchanged.

Improvetrol of blood pressure with antihypertensive therapy on a national level over time would have been d conexpected to reduce the hospitalization rate for aortic dissection, Krumholz group noted.

As to why that was not seen in the study, they suggested, "This may partly be because of advancements in noninvasive diagnostic technology, such as the development of multidetector CT resulting in rapid high definition CT angiography from neck to abdomen, leading to increased detection of dissection."

The reason for the improvement in mortality in operative patients might have been "subtle improvements on various fronts," such as neuroprotection, improved intraoperative and postoperative pharmacological therapy, operative algorithm and standardized cannulation techniques, and development of care teams, the researchers pointed out.

"Additionally, part of the improvement in mortality seen with type B dissection could be possible because of the increasing use of the endovascular approach in the treatment of surgically high-risk patients."

Limitations included unknown generalizability to younger populations and Medicare Advantage patients and potential residual confounding.