Ultrasound saves renal transplantees’ lives

Stress echocardiography can accurately predict the onset of cardiovascular disease in patients waiting for kidney transplants, according to a study presented in June at the American Society of Echocardiography meeting.

Cardiovascular disease is the most common cause of death in patients undergoing renal transplantation. Clinical evidence shows that detection and management of cardiovascular disease before a transplant reduces post-transplant morbidity and mortality. Findings from a Michigan research team could have important implications for about 64,000 U.S. patients currently waiting for a transplant.

"Stress echocardiography is a very effective screening tool in identifying chronic kidney disease patients who are at high and low risk for cardiac complications after renal transplantation," said principal investigator Dr. Cristina Tita, a cardiologist at the Henry Ford Hospital in Detroit.

Tita and colleagues retrospectively reviewed data from 149 consecutive patients, split nearly evenly between women and men and 65% African American. Patients underwent stress echocardiography before and after transplantation and were followed for nearly three years.

The investigators found that patients with abnormal pre- and post-transplant stress echocardiograms had a 30% chance of having a major cardiac event in the first year after surgery compared with a 3% chance for those with a negative scan.

Of 149 patients, 139 had a negative stress echocardiography, while 10 had a positive test. Twenty-four patients suffered major adverse cardiovascular events during follow-up:

• four nonfatal myocardial infarctions

• nine cardiac deaths

• two coronary revascularizations

• one congestive heart failure

• eight transient ischemic attacks/cerebrovascular accidents

The specificity and negative predictive value for stress echocardiography regarding major adverse cardiovascular events were 95% and 96%, respectively. Sensitivity and positive predictive value lagged at 37% and 33%, respectively.

The event rates for negative and positive stress echo results in the first year post-transplant were 3.6% and 30%, respectively. Overall follow-up event rates for negative and positive scans were 14% and 50%, respectively.

In addition to positive stress heart sonography, other predictors of major cardiovascular events post-transplant were hemoglobin levels under 11 gm/dL and the need for calcium channel blockers.

Sixty-five percent of patients who underwent stress echocardiography prior to renal transplantation were diabetics. In addition, 96% suffered from hypertension, 10% had ejection fraction under 50%, and 11% had prior coronary artery disease.

Stress echocardiography provides an excellent tool for post-transplant risk stratification and management. The routine use of aspirin, statins, and beta blockers to treat these patients, however, needs to be prospectively studied, researchers said.

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