JACC: Ascending aortic dilation guidelines may need re-examining

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Aortic valve replacement (AVR) alone may be sufficient to prevent further aortic expansion in patients with moderate post-stenotic dilation of the ascending aorta, according to a study published Aug. 2 in the Journal of the American College of Cardiology.

“Aortic stenosis is becoming one of the most frequent indications for surgery in the western world, with enormous clinical and economic implications; both the industry and surgical communities are employing considerable resources to develop new methods of treatment of the disease,” Mario Gaudino, MD, from the division of cardiac surgery at Catholic University in Rome, and colleagues wrote.

Because appropriate treatment of post-stenotic ascending aortic dilation has been poorly investigated, Gaudino and colleagues set out to evaluate the aortic dimensions in patients with moderate post-stenotic ascending aorta dilation (50 to 59 mm) who underwent AVR at Catholic University between January 1990 and December 2000.

During the study, 93 patients with severe isolated calcific aortic valve stenosis were enrolled and were followed for a mean of 14.7 years. Patients had a mean age of 67.1 years and most were NYHA Class I or II.

Gaudino and colleagues reported that the operative mortality rate was 1 percent. Sixteen patients died during follow-up and two patients had to be reoperated on because of valve dysfunction. During the study period, no patients experienced acute aortic events including rupture, dissection or pseudoaneurysm, and no patients underwent reoperation on the aorta. No significant increases in aortic dimensions were noticed and the mean aortic diameter was 57 mm at the end of the follow-up versus the 56 mm recorded during the pre-operative period. The mean aorta expansion rate was 0.3 mm per year.

“The approach to patients with moderate post-stenotic dilation of the ascending aorta remains controversial,” Gaudino and colleagues wrote. “In patients with connective tissue disorder or bicuspid aortic valve, the intrinsic disease of the vascular media mandates ascending aorta replacement.” However, the authors noted that when aortic dilation occurs after modified flow patterns through the stenotic valve and the vascular wall histology is normal, AVR can help interrupt the process.

“Ascending aorta replacement should be considered only for very young patients with extremely long-life expectancy,” the authors said.

Current American College of Cardiology (ACC)/American Heart Association (AHA) guidelines recommend replacing the ascending aorta at the time of AVR if the ascending aorta is more than 5 cm or if the ascending aorta is more than 4.5 cm in bicuspid patient, according to an accompanying editorial written by Donald D. Glower, MD, of the Duke University Medical Center in Durham, N.C. And while Gaudino and colleagues noted that the current study findings contradict the current guidelines for treating the ascending aorta, they said that the current guidelines do not include specific recommendations for subtypes of aortic dilations.

Glower noted that if the the current findings are confirmed to be accurate, then ACC/AHA guidelines should be revised to include more specific information regarding patient groups (e.g., Marfan, bicuspid, tricuspid). “Evidence supports the contention of Gaudino et al that size alone is not enough to indicate replacement of the ascending aorta in many patients with aortas of less than 6 cm in diameter.

“Guidelines are just guidelines. Guidelines need to be applied to individual patients by knowledgeable physicians,” Glower concluded.