Searching for the Cause of HFpEF in Older Adults
- To reinforce that heart failure in the presence of a preserved ejection fraction has a diverse set of causes.
- To define the underlying etiology, which is essential for appropriate treatment.
- To highlight features of an infiltrative cardiomyopathy as a cause of heart failure with preserved ejection fraction (HFpEF) in order to facilitate early diagnosis.
You are asked to evaluate an 82-years-old woman with exertional dyspnea and near-syncope as a second opinion. According to her son, who accompanied her to the appointment, she has been slowing down for the past year or two. She has had previous evaluations at three different medical centers for these symptoms. She has been treated at each institution with diuretics for acute decompensated heart failure and, because of a positive troponin, has undergone three cardiac catheterizations, none of which demonstrated significant coronary artery disease.
Currently, she can walk about two blocks and one flight of stairs because of dyspnea on exertion compatible with New York Heart Association (NYHA) Class IIB symptoms. She denies paroxysmal nocturnal dyspnea (PND) and orthopnea, although she does have nocturia. She has no bloating or edema. She has learned to eat a low-sodium diet and check her weight daily.
Family History: Non-contributory
Current Medications: Isosorbide mononitrate 60 mg daily, Lasix 20 mg daily, Lipitor 10 mg daily, Evista 60 mg daily, Citracal citrate 2 grams daily, zinc 500 mg daily, vitamin C 500 mg daily, vitamin E 400 mg daily, iron 1200 mg daily.
Review of systems: No easy bruising, no history of carpal tunnel syndrome, arthritis affecting her knees and back; bilateral hearing aids; palpitations with activity; no history of hypertension; inflammatory bowel disease, in remission, no melena or bright red blood per rectum.
Physical exam: Amicable elderly woman in no acute distress. She is 5 feet, 3 inches, weighs 157 pounds. Her heart rate was 78 bpm, increased to 100 bpm with a hall walk. Her blood pressure was 124/80; O2 saturation was 96% on room air and stayed at 96% with activity. Her skin was warm. She had JVP at 10 cm with a rapid x and y descent. Her lung fields were clear bilaterally without an audible gallop or murmur. She had crackles at her bases. Her abdomen was soft and non-tender with no organomegaly. She had trace ankle edema
Previous workup available for review includes the following:
- An echocardiogram showed a left atrium of 43 mm, septal wall thickness was 13 mm, left ventricular internal dimension in diastole was 42 mm, EF was 73%, her E:A ratio was 0.72 and right ventricular systolic pressure (RVSP) was estimated at 38 mm Hg. She had mild aortic regurgitation (AR), no aortic stenosis (AS), mild mitral regurgitation (MR), mild mitral annular calcification, and trivial pericardial effusion.
- A left heart catheterization demonstrated that left ventricular (LV) pressure was 100/12 mm Hg, her aortic pressure was 100/55 mm Hg with a mean of 70 mm Hg. Coronary angiography revealed a right coronary artery lesion of 30% in the mid-portion, the left main was normal, proximal left anterior descending (LAD) artery was 30-50% calcified lesion, proximal left circumflex was mildly diseased and distally had a 30-50% stenosis. She had an EF of 55% on left ventriculogram and 1+ MR.
- A right heart catheterization at rest and with exercise was performed two years ago. Her resting right atrial (RA) pressure was 12 mm Hg, RV was 35/12 mm Hg, and pulmonary artery (PA) pressures were 32/12 mm Hg with a mean of 20 mm Hg. Pulmonary capillary wedge pressure was 12 mm Hg. PA saturation was 62%. Her aortic saturation was 92%, resting cardiac output of 5 L/min, cardiac index was 2.8 L/min/m2, and her pulmonary vascular resistance (PVR) was 1.6. With exercise, her blood pressure went to 110/60 with a mean of 77 mm Hg. Her aortic saturation stayed at 93%, her pulmonary artery saturation was 57%, and pulmonary capillary wedge pressure rose to 20 mm hg, PA pressures increased to 55/20 mm Hg with a mean of 32 mm Hg. Her cardiac output fell to 4.4 L/min, her cardiac index was 2.5 L/min/m2, and her PVR was 2.7.
- Laboratory testing available for review: Blood urea nitrogen (BUN) of 26, creatinine of 1.2, albumin of 3.5, normal liver function tests (LFTs), an estimated glomerular filtration rate of 42 ml/min/m2. Her total cholesterol was 150, LDL of 80, hemoglobin of 10.9 with a platelet count of 194 and a white count of 8.7.
- Laboratory testing today including a troponin that was positive at 0.45 ng/ml (normal <0.02 ng/ml), and her B-type natriuretic peptide (BNP) level was 871 pg/ml (normal <100 pg/ml). Her potassium was 4, sodium was 140, BUN 29, creatinine 1.34. Her glucose was 85.
- Electrocardiogram (ECG): Sinus rhythm, leftward axis, probable left atrial enlargement, poor R-wave progression, normal voltage (Figure 1).
Which of the following blood tests is most likely to suggest an important, previously unrecognized diagnosis in this patient?