As America’s population ages, heart failure diagnoses are on the rise — especially the type caused by a stiff, thickened heart muscle. The heart pumps adequately but can’t relax, causing fluid to back up into the lungs, leading to symptoms such as breathlessness and fatigue.
Doctors refer to this form of heart failure as “heart failure with preserved ejection fraction,” or HFpEF. About half of all heart failure diagnoses fall into this category, yet the condition has proved challenging to treat. But cardiologists are now recognizing that about 10% to 15% of people with stiff, failing hearts may have cardiac amyloidosis.
“We used to think of cardiac amyloidosis as a rare condition with an inexorably progressive and fatal course,” says Dr. Sharmila Dorbala, associate professor of radiology at Harvard Medical School. Now, there’s reason for optimism, she says. Advances in cardiac imaging have improved cardiologists’ ability to diagnose the condition. And last year, the FDA approved tafamidis (Vyndaqel), the first drug to treat the most common form of cardiac amyloidosis.
Amyloid in the heart
Amyloidosis is a group of diseases characterized by clumps of abnormal protein (amyloid) in various tissues throughout the body. One form, known as beta amyloid, builds up in brain tissue, creating the plaques that characterize Alzheimer’s disease. But there is no known connection between cardiac amyloidosis and Alzheimer’s disease.
Most cases of cardiac amyloidosis are known as ATTR amyloidosis, which has an inherited form and a non-inherited form. There are more than 130 different genetic variations seen in inherited forms of ATTR, some of which lead to cardiac symptoms in people in their 40s and 50s. One variant, found in about 4% of African Americans, usually doesn’t cause symptoms before people reach their 60s. But only a small number of people with this particular variant develop the disease. The non-inherited form of ATTR is a disease of aging; it mainly affects people ages 70 and older. Once considered rare, this non-inherited form is now being diagnosed more frequently.
Cardiac amyloidosis can be tricky to diagnose as symptoms can be vague, but certain red flags sometimes provide clues, says Dr. Dorbala. Heart failure, irregular heart rhythms, and an intolerance to certain blood pressure drugs can raise the suspicion of amyloidosis. So can certain musculoskeletal conditions, including a torn tendon in the upper arm, carpal tunnel syndrome (a pinched nerve in the wrist), and -spinal stenosis (a narrowing of the space around the lower spine).
Diagnosis of amyloidosis
To diagnose any type of heart failure, the first test is usually an ultrasound of the heart (echocardiogram). But in the early stages of cardiac amyloidosis, the echocardiogram may appear normal. The classic sign of amyloidosis — a thickening of the heart’s left ventricle — is seen in advanced amyloidosis. Sometimes, this is mistakenly attributed to chronic, untreated high blood pressure, especially in African Americans. But ventricular thickening from high blood pressure is now far less common, thanks to improved blood pressure treatments, says Dr. Dorbala. “Now, when we see a thickened ventricle, particularly in someone with well-controlled blood pressure, we’re more concerned about cardiac amyloidosis,” she adds.
Until about five years ago, doctors relied on a biopsy of the heart tissue to check for cardiac amyloidosis. Today, a noninvasive imaging test that uses a radioactive tracer to illuminate areas of amyloid in the heart is available in most medical centers. It can accurately diagnose ATTR cardiac amyloidosis without a heart biopsy.
A new (but costly) therapy
The approval of tafamidis may be changing the once-dismal outlook for cardiac amyloidosis. Studies showed that tafamidis helps to keep people out of the hospital and to live longer, compared with those taking a placebo. However, the drug’s list price is $225,000 a year, making it unaffordable even for some people with insurance if they have high copayments. An inexpensive generic drug, diflunisal, might help slow the progression of ATTR amyloidosis, but side effects limit its use. Still, the increasing awareness and research on amyloidosis may lead to new ways to diagnose early disease when treatments may be most effective, and someday may make it possible to prevent the disease, Dr. Dorbala says.Image: © kali9/Getty Images
Bible verses for today’s meditation and inspiration: Matthew E. McLaren
Rejoice always, pray continually, give thanks in all circumstances; for this is God’s will for you in Christ Jesus. 1 Thessalonians 5:16-18 NIV
The Lord your God is with you, the Mighty Warrior who saves. He will take great delight in you; in his love he will no longer rebuke you, but will rejoice over you with singing. Zephaniah 3:17 NIV
Rejoice in the Lord always. I will say it again: Rejoice! Philippians 4:4 NIV
Be joyful in hope, patient in affliction, faithful in prayer. Romans 12:12 NIV
When anxiety was great within me, your consolation brought me joy. Psalm 94:19 NIV
The Lord has done it this very day; let us rejoice today and be glad. Psalm 118:24 NIV
Though the fig tree does not bud and there are no grapes on the vines, though the olive crop fails and the fields produce no food, though there are no sheep in the pen and no cattle in the stalls, yet I will rejoice in the Lord, I will be joyful in God my Savior. Habakkuk 3:17-18 NIV
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