Helping WG and MPA Patients Avoid Cardiac Events

Helping WG and MPA Patients Avoid Cardiac Events

May 2011

A new diagnostic model will help physicians identify those at risk for cardiovascular events among patients newly diagnosed with Wegener’s granulomatosis (WG) and microscopic polyangiitis (MPA). This is particularly valuable because patients with WG and MPA are 3.7 times more likely than those without vasculitis to die from a cardiovascular event in the first five years following diagnosis. Identifying those most at risk is critical.

“This study allows us to quantify an individual patients’ risk,” says principal investigator Ravi Suppiah, consultant rheumatologist at the Auckland (N.Z.) and Counties Manukau District Health Boards. “Identifying patients at most risk may allow closer monitoring and allow early intervention.”

A Higher Risk
There’s not yet a conclusive reason why WG and MPA patients are at a higher risk; several ideas are being researched.

“The main theory is that the inflammation of the blood vessels that occurs in vasculitis causes long term damage to the inside lining of the artery and makes it prone to developing atherosclerosis,” Suppiah explains. “In addition, the steroid medicines we use to treat vasculitis are known to cause diabetes and high blood pressure which are well-recognized risk factors for a cardiovascular event.” Kidney failure, which frequently develops as a result of WG or MPA, is another common risk for cardiovascular disease.

A Model for Diagnosis
Suppiah began working on a diagnostic tool as a rheumatology fellow at the Nuffield Orthopaedic Centre and the University of Oxford in the U.K. The model was developed and tested first a group of in newly-diagnosed WG and MPA patients, as well as those with an existing diagnosis who were having a flare at the time they were enrolled in the trial.

“Their cardiovascular risk was calculated at entry into the trial and predicted cardiovascular events very well in this group,” Suppiah says.

He found that WG or MPA patients who have diastolic hypertension at the time they first develop vasculitis or during a flare have a higher risk of an event.  Patients who are older at the time of onset also are more at risk.

His research also found that patients with a positive blood test for PR3 ANCA — found in most patients with WG — have a lower risk than those WG and MPA patient without the blood marker. Unfortunately, however, the risk of cardiac events is still higher than the general population.

The model has not been yet been tested in patients with an established WG or MPA diagnosis who are in disease remission.

The Next Stage
While assessing a patients’ risk of cardiac events is an important development, Suppiah says more study is needed to determine what can be done to avert an event altogether.

“All the current recommendations are extrapolated from modifiable risk factors in the general population,” he says. “At the moment we do not know whether altering these traditional risk factors — smoking, hypertension, being overweight, diabetes, etc. — will reduce the risk of having a cardiovascular event in patients with vasculitis. Nor do we know whether different treatments for vasculitis alter this risk. Additional research is needed.”

A Benefit to Patient and Doctor
Despite the unknowns, the study’s preliminary findings are important to patients and physicians.

“Using the results of our research, patients can understand their risk of having a cardiovascular event in the next five years,” Suppiah says. “This will enable them to make better-informed decisions regarding their health behaviours such as smoking and making sure that their blood pressure, cholesterol, weight and diabetes are well controlled.”

For physicians, the model can lead to better preventive care and more favourable patient outcomes. It also helps further the research agenda.

“Being able to quantify cardiovascular risk for their patients may allow them to discuss and recommend preventative treatment strategies to their patients,” Suppiah notes. “Additionally, being able to calculate cardiovascular risk will enable researchers to test treatment strategies that reduce this risk.”