Is it CHF? A new blood test can tell you
Is it CHF? A new blood test can tell you
When a patient complains of shortness of breath, congestive heart failure (CHF) may be one of the first things you suspect, but a definitive diagnosis can be difficult. Now a new blood test that measures a cardiac biomarker, the terminal prohormone of B-type natriuretic peptide (NT-proBNP), can give you an answer within minutes.
Researchers looked at 600 ED patients with shortness of breath, who were clinically evaluated and given a blood test to measure NT-proBNP levels. The protein’s concentrations were significantly higher in patients with heart failure, and highest in those with the most severe symptoms.1
"We found that testing with the NT-proBNP assay was an extremely accurate way to identify or exclude heart failure in patients with shortness of breath," says James Januzzi Jr., MD, associate director of the coronary care unit at Boston-based Massachusetts General Hospital and the study’s lead author.
Recently, a patient with a history of chronic obstructive pulmonary disease (COPD) and prior CHF from coronary artery disease came to the ED with shortness of breath that persisted after treatment with nebulized inhalers and steroids.
The patient’s history and physical examination weren’t clearly consistent with COPD or CHF, and a chest X-ray showed only nonspecific findings, but 35 minutes later, blood test results for NT-proBNP revealed a diagnosis of CHF. "The patient was treated with diuretics with significant improvement," reports Januzzi.
There are many possible diagnoses when a patient complains of shortness of breath, says Trisha Flanagan, RN, MSN, an ED clinical nurse specialist at Massachusetts General. "It could be a panic attack, metabolic problem, heart failure, asthma, allergic reaction, or even the only sign of a myocardial infarction," she says.
Triage nurses perform a quick assessment including a medical history and vital signs, and they determine acuity using the Emergency Severity Index five-level triage scale, followed by a more in-depth assessment by a primary nurse, says Flanagan. "CHF is not something that will immediately declare itself, but the initial nursing assessment will point you in the right direction," she says.
In the event that CHF goes undetected in the ED, patients may go into pulmonary edema, with the ability to oxygenate severely compromised, says Flanagan. "CHF can be tricky to diagnose initially, so anything that points you in that direction is helpful," she says. "We haven’t even been doing the BNP testing all that long, and even that was a great advance — now this more refined test is another new weapon in our arsenal."
Missing a heart failure diagnosis can put patients at high risk for serious adverse outcomes, including death, but overdiagnosis may lead patients to receive unnecessary treatment, says Januzzi.
From Januzzi’s experience as a clinician, there have been numerous situations when he wasn’t certain a patient had CHF. "In the past, I would have to send the patient down a whole pathway of possible tests, but now with a single blood test I may be able to make or exclude the diagnosis very simply," he says. "Half an hour later when I get the result of the blood test, I have an answer."
If the test is negative, a diagnosis of CHF can be ruled out definitively, so echocardiograms aren’t needed, which makes the test very cost-effective, he adds. "We believe NT-proBNP testing should now become a routine component of evaluation for patients with shortness of breath in emergency departments," says Januzzi.
He estimates that only about 50% of EDs use BNP testing, with only a handful of EDs using the new blood test, but Januzzi expects that to increase dramatically in the near future. "This was the first large scale data supportive of the newer versions of the blood tests, which will eventually replace the older versions, so it’s very important to pave the way for future use," he says. "This will soon be standard of care in the ED."
1. Januzzi JL, Camargo CA, Anwarruddin S, et al. The N-terminal pro-BNP investigation of dyspnea in the emergency department (PRIDE) study. Am J Cardiol 2005; 95:948-954.
For more information on diagnosing congestive heart failure in the ED, contact:
- Trisha Flanagan, RN, MSN, Emergency Department, Clinical Nurse Specialist, Massachusetts General Hospital, 55 Fruit St., Boston, MA 02114. Telephone: (617) 724-4932. E-mail: [email protected].
- James L. Januzzi Jr., MD, FACC, Cardiology Division, Massachusetts General Hospital, Yawkey Building, Suite 5984, 55 Fruit St., Boston, MA, 02114. Telephone: (617) 726-3443. Fax: (617) 643-1620. E-mail: [email protected].
Subscribe Now for Access
You have reached your article limit for the month. We hope you found our articles both enjoyable and insightful. For information on new subscriptions, product trials, alternative billing arrangements or group and site discounts please call 800-688-2421. We look forward to having you as a long-term member of the Relias Media community.