335. Guidelines: 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure – Question #29 with Dr. Michelle Kittleson

The following question refers to Section 7.8 of the 2022 AHA/ACC/HFSA Guideline for the Management of Heart Failure.The question is asked by Stony Brook University Hospital medicine resident and CardioNerds Intern Dr. Chelsea Tweneboah, answered first by Mayo Clinic Cardiology Fellow and CardioNerds Academy Chief Dr. Teodora Donisan, and then by expert faculty Dr. Michelle Kittleson.The Decipher the Guidelines: 2022 AHA / ACC / HFSA Guideline for The Management of Heart Failure series was developed by the CardioNerds and created in collaboration with the American Heart Association and the Heart Failure Society of America. It was created by 30 trainees spanning college through advanced fellowship under the leadership of CardioNerds Cofounders Dr. Amit Goyal and Dr. Dan Ambinder, with mentorship from Dr. Anu Lala, Dr. Robert Mentz, and Dr. Nancy Sweitzer. We thank Dr. Judy Bezanson and Dr. Elliott Antman for tremendous guidance.Enjoy this Circulation 2022 Paths to Discovery article to learn about the CardioNerds story, mission, and values.


Question #29




A 69-year-old man was referred to the cardiology clinic after being found to have a reduced left ventricular ejection fraction and left ventricular hypertrophy. For the last several months he has been experiencing progressively worsening fatigue and shortness of breath while getting to the 2nd floor in his house. He has a history of bilateral carpal tunnel syndrome and chronic low back pain. He takes no medications. On exam, his heart rate is 82 bpm, blood pressure is 86/60 mmHg, O2 saturation is 97% breathing ambient air, and BMI is 29 kg/m2. He has a regular rate and rhythm with normal S1 and S2, bibasilar pulmonary rales, and 1+ pitting edema in both legs. EKG shows normal sinus rhythm with a first-degree AV delay and low voltages. Transthoracic echocardiogram shows a moderately depressed LVEF of 35-39%, severe concentric hypertrophy with a left ventricular posterior wall thickness of 1.5 cm and strain imaging showing globally reduced longitudinal strain with apical sparring. There is also biatrial enlargement and a small pericardial effusion. A pharmacologic nuclear stress test did not reveal any perfusion defects. A gammopathy panel including SPEP, UPEP, serum and urine immunofixation studies, and serum free light chains are unrevealing. A 99mTc-Pyrophosphate scan was positive with grade 3 uptake. In addition to starting diuretics, what is the next most appropriate step for managing for this patient?




A


Start metoprolol succinate




B


Start sacubitril/valsartan




C


Perform genetic sequencing of the TTR gene




D


Perform endomyocardial biopsy






Answer #29




Explanation


The correct answer is C – perform genetic sequencing of the TTR gene.
 
This patient has findings which raise suspicion for cardiac amyloidosis. There are both cardiac (low voltages on EKG and echocardiogram showing marked LVH with biatrial enlargement and small pericardial effusion as well as a characteristic strain pattern) and extra-cardiac (bilateral carpal tunnel syndrome and low back pain) features to suggest amyloidosis. The diagnosis of cardiac amyloidosis requires a high index of suspicion and most commonly occurs due to a deposition of monoclonal immunoglobulin light chains (AL-CM) or transthyretin (ATTR-CM). ATTR may cause cardiac amyloidosis as either a pathogenic variant (ATTRv) or as a wild-type protein (ATTRwt).
 
Patients for whom there is a clinical suspicion for cardiac amyloidosis should have screening for serum and urine monoclonal light chains with serum and urine immunofixation electrophoresis and serum free light chains (Class 1, LOE B-NR). Immunofixation electrophoresis (IFE) is preferred because serum or urine plasma electrophoresis (SPEP or UPEP) are less sensitive. Together, measurement of serum IFE, urine IFE, and serum FLC is >99% sensitive for AL amyloidosis.