Aortic Dissection Mortality Linked to Low Surgical Volume

Larry Hand

May 02, 2013

Risk for mortality from emergency surgical repair of acute aortic dissection may be almost twice as high among surgeons and institutions that perform the lowest volume of operations compared with those surgeons and institutions that perform the highest volume of operations, according to an article published in the May issue of the Annals of Thoracic Surgery.

Joanna Chikwe, MD, from the Department of Cardiothoracic Surgery, Mount Sinai Medical Center, New York City, and colleagues analyzed the records of 5184 patients who underwent surgical repair of acute aortic dissection between 2003 and 2008. They also analyzed records with data on 24,777 acute thoracic repair patients during an entire decade (between 1998 and 2008). They obtained patient outcomes from the Nationwide Inpatient Sample database, maintained by the Agency for Healthcare Research and Quality.

The researchers found that a strong inverse relationship existed between in-hospital mortality and both institutional and surgeon volume (measured separately).

For surgeons, those who performed the operation less than once a year had a mean operative mortality of 27.5% compared with surgeons who performed the operation on average 5 times a year (odds ratio, 1.78; 95% confidence interval, 1.39 - 2.29; P < .001). For institutions, operative mortality came to 27.4% for those in which 3 or fewer operations took place a year compared with 16.4% for institutions in which more than 13 such operations occurred a year (P < .001). The researchers used logistic regression analysis to reach their conclusion, adjusting for age, sex, race, payer status, preoperative comorbiditities, and hospital location, bed size, and teaching status.

Overall, however, national operative mortality decreased from 23% in 1998-2000 to 19% in 2005-2008.

"Aortic dissection is usually an emergency, which limits the ability of patients to choose where they want to be treated," Dr. Chikwe said in a news release. "However, our data suggest that in settings where physicians may be able to refer a patient to several surgical centers without delaying surgery, the patient's chances of surviving are greatest in the hospitals that specialize in these types of procedures."

Limitations of the study include the administrative nature of the Nationwide Inpatient Sample, which has less information regarding comorbidities and operative details than some clinical registries.

However, the study has implications for clinical practice, the researchers write: "Given declining duration and intensity of cardiac surgical training, and rapid access in most urban centers to surgical teams with focused expertise in management of aortic dissection, it may no longer be appropriate to emphasize the speed of surgical transfer beyond speed of transfer to an experienced center."

This research was supported by the Mount Sinai School of Medicine Summer Research Program and the American Federation for Aging Research, Medical Research. Dr. Chikwe has disclosed a financial relationship with Edwards Lifesciences. One coauthor has disclosed a financial relationship with Medtronic Inc, and Edwards Lifesciences. The other authors have disclosed no relevant financial relationships.

Ann Thorac Surg. 2013;95:1563-1569. Abstract