Sleep apnea and pulmonary hypertension affect in-hospital outcomes of noncardiac surgery

Research Activities, July 2011, No. 371

Patients undergoing noncardiac surgery are at higher risk of negative outcomes developing before hospital discharge if they have either pulmonary hypertension (PHTN) or sleep apnea (SA), according to two new studies. Both studies by Stavros G. Memtsoudis, M.D., Ph.D., of the Weill Medical College of Cornell University, and colleagues used the National Inpatient Sample (NIS) databases for the years 1998 to 2006 (or 2007, in the newer study) to test whether the two lung-related conditions were risk factors for perioperative complications or death.

The NIS is an annual all-payer database of inpatient discharges, collecting data on approximately 8 million hospital discharges annually as part of the Agency for Healthcare Research and Quality (AHRQ) Healthcare Cost and Utilization Project. Both studies, described here, were funded in part by a grant from the AHRQ (HS16075) to the Weill Medical College of Cornell University Center for Education and Research on Therapeutics (CERT).

For more information on the CERTs program, visit

Memtsoudis, S. G., Ma, Y., Chiu, Y. L., and others. "Perioperative mortality in patients with pulmonary hypertension undergoing major joint replacement." (2010, November). Anesthesia Analgesia 111(5), p. 1110-1116.

Patients with PHTN are at increased risk of dying after total hip arthroplasty (THA) or total knee arthroplasty (TKA) than patients undergoing these surgeries who do not have PHTN, the researchers found. Using records from the NIS for 1998 through 2006, the researchers identified 670,516 entries for discharges of patients following TKA and 360,119 for THA. Of these patients, 2,184 (weighted national average of 0.3 percent) and 1,359 (weighted national average of 0.4 percent), respectively, had the diagnosis of PHTN.

Among patients with PHTN, 18 percent of those undergoing TKA and 20 percent of those undergoing THA had primary PHTN—the more serious form of this disease. Patients with PHTN tended to be older, were more frequently female, and had a greater number of other health problems. Compared with matched controls having the same surgery, perioperative mortality among patients with PHTN was 3.7 or 4.6 times higher (for those undergoing THA or TKA, respectively). A fatal outcome was at least three times more frequent in patients with primary than with nonprimary PHTN.

Memtsoudis, S., Liu, S. S., Ma, Y., and others. "Perioperative pulmonary outcomes in patients with sleep apnea after noncardiac surgery." (2011, January). Anesthesia Analgesia 112(1), p. 113-121.

Among patients undergoing noncardiac surgery, SA is an independent risk factor for pulmonary complications of surgery, the researchers found. As in the pulmonary hypertension study, the researchers used NIS data from 1998 through 2007 to identify 2,610,441 patients who had orthopedic and 3,441,262 who had general surgery during this period.

Among these patients, SA was diagnosed in 51,509 patients who underwent general surgery (weighted national average, 1.4 percent) and in 65,774 patients who underwent orthopedic surgery (weighted national average, 2.5 percent). For either procedure, males had a higher prevalence of SA compared with the general surgical population. Patients with SA had a greater number of other health problems, and were approximately five times more likely to be obese. Three pulmonary complications (aspiration pneumonia, adult respiratory distress syndrome, and intubation/mechanical ventilation) developed more frequently among patients with SA than their matched controls regardless of the type of surgery. However, pulmonary embolism was significantly more common among SA patients than their matched controls after orthopedic surgery compared with general surgery.

Current as of July 2011
Internet Citation: Sleep apnea and pulmonary hypertension affect in-hospital outcomes of noncardiac surgery: Research Activities, July 2011, No. 371. July 2011. Agency for Healthcare Research and Quality, Rockville, MD.