AAA: To Screen or Not to Screen?

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Source: GE Healthcare

Abdominal aortic aneurysms (AAAs) have very few warning signs or symptoms, making untreated patients ticking time bombs. In fact, 80 to 90 percent of patients with a ruptured AAA die before ever reaching the hospital. While most aneurysms are found incidentally during routine ultrasound exams, initiatives focusing on improving screening for patients most at risk for AAA have surfaced and protocols have emerged to help streamline care upon diagnosis.

In 2007, Congress passed the SAAAVE Act, a measure that allows patients entering Medicare to undergo one-time ultrasound screening for AAA. Because the disease is four times more common in men, screening is currently limited to men older than 65 years who have smoked at least 100 cigarettes during their lifetime, and patients with a family history of AAA. However, more than half of the existing AAA cases—approximately 569,000 cases—occur among patients ineligible to undergo screening under these criteria. Thus, is more screening necessary?

Get your ducks in a row

Harborview Medical Center in Seattle treats 30 to 40 ruptured aneurysms annually. Establishing a protocol was imperative to providing the best AAA care quickly, says Benjamin W. Starnes, MD, chief of vascular surgery at Harborview. First, the facility connected its PACS to outlying PACS at surrounding facilitates to enable the transfer of images. Now, Starnes and colleagues can view AAA patient images earlier and make the decision of how to treat the rupture, before the patient reaches the hospital.

In 2007, Harborview integrated the same AAA protocol that doctors from the Albany Medical Center in Albany, N.Y., instituted in 2002 (J Vasc Surg 2006;44:1-8). After the protocols were implemented, Albany's mortality rate was a mere 18 percent, significantly lower than the standard 32 to 70 percent mortality rate for open surgical repair.

A multidisciplinary approach to AAA that brings together vascular surgeons, emergency department physicians, anesthesiologists, operating room and radiology staff is vital to expediting AAA care. After the care team is formed, an emergent CT scan is performed on presenting AAA patients who are hemodynamically stable with blood pressure levels less than 80 mm Hg. The patient is then prepped under local anesthesia and kept awake after which an aortic occlusion balloon is placed under x-ray guidance. Patients are kept awake to maintain the patient's physiologic state, Starnes offers.

Physicians must then decide whether to treat patients with endovascular aneurysm repair (EVAR) or with surgery. While surgical repair remains the gold standard, it also has been linked to high mortality rates of 35 to 80 percent.

However, ample evidence has shown EVAR techniques may be less risky and improve complication rates. For example, one study showed that patients who underwent EVAR had a lower risk of death in the first 30 days after the procedure when compared with patients who underwent open repair, 0.2 versus 2.3 percent (JAMA 2009;302[14]:1535-1542).

While such protocols can decrease mortality, facility wide deployment may be difficult. A major challenge is attempting to change the mindset of providers and create a seamless transition from the ED to the operating room. "For example, it took time for the anesthesiologists at Harborview to become comfortable with keeping hypotensive patients with BPs equal to 80 mm Hg awake for a ruptured AAA repair," Starnes offers. "However, after a few of these cases, anesthesiologists realize that this technique saves lives."

Also, integrating protocols works. Prior to Harborview's protocols, "only 42 percent of our patients survived," says Starnes. Two years after the protocols were deployed, mortality dropped to 32 percent, the lowest in 30 years, he says. Thirty-day mortality rates dropped from 61.5 percent to 29 percent within the first six months.

Similarly, Alex S. Tretinyak, MD, and colleagues at the Minneapolis Heart Institute (MHI), who treat 10 to 15 AAA cases annually, instituted an AAA algorithm in 2008. "You have to compress the triage, transfer and plan for these patients in a very short period of time because they are very sick and require immediate treatment," says Tretinyak, a vascular surgeon at MHI.

In addition to creating a standard operating procedure to receive these patients, MHI took it a step further and went to 24 referring centers that transfer AAA patients to educate ED staff. MHI developed order sets (checklists for appropriate