DOI: 10.12890/2025_005785
What are the safest and easiest extra-cardiac biopsy sites for the diagnosis of wild-type transthyretin cardiac amyloidosis? Confirmation of the diagnosis by biopsy of the pectoralis muscle during pacemaker insertion
Authors
michitokitatsumasa@gmail.com
Keywords
Bone-avid tracer, pectoralis major muscle, permanent pacemaker implantation, sick sinus syndrome, wild-type transthyretin amyloidosisAbstract
Background: The use of nonbiopsy diagnosis of wild-type transthyretin cardiac amyloidosis (ATTRwt-CA) has grown worldwide. However, in specific scenarios, a biopsy of the myocardium or involved tissues must be conducted to confirm deposition of amyloid transthyretin (ATTR).
Case report: An 83-year-old woman was diagnosed with decompensated heart failure, sick sinus syndrome (SSS), and an atrial septal defect (ASD). Cardiac amyloidosis was also suspected. Technetium-99m-labelled pyrophosphate (Tc-99m-PYP) scintigraphy revealed that tracer uptake was greater in the right ventricular (RV) myocardium than in the left. Tc-99m-PYP uptake in many of the skeletal muscles, including the pectoralis major, was also observed. Permanent pacemaker implantation for SSS was performed without complications. A sample of the pectoralis major was resected while forming the pocket for the pacemaker and was used to confirm deposition of ATTR through Congo red staining and immunohistochemical analysis. No mutations were detected in the transthyretin gene. Therefore, the patient was diagnosed with ATTRwt-CA and treatment with tafamidis was initiated.
Conclusion: Histological confirmation of amyloid type is generally needed when a patient presents with suspected immunoglobulin light chain cardiac amyloidosis, visual grade 1 myocardial Tc-99m-bone-avid isotope uptake, visual grade 2–3 uptake with plasma cell dyscrasia, or suspected infrequent types of amyloidosis. In our patient, a rare Tc-99m-PYP uptake pattern due to RV overload from ASD was observed, and a biopsy was required to confirm amyloid type. A biopsy of the pectoralis major may be performed when a permanent pacemaker is implanted, and it can be useful for confirming deposition of ATTR.
References
- Gillmore JD, Maurer MS, Falk RH, Merlini G, Damy T, Dispenzieri A, et al. Nonbiopsy diagnosis of cardiac transthyretin amyloidosis. Circulation 2016;133:2404–2412. doi: 10.1161/CIRCULATIONAHA.116.021612
- Gonzalez-Lopez E, McPhail ED, Salas-Anton C, Dominguez F, Gertz MA, Dispenzieri A, et al. Histological typing in patients with cardiac amyloidosis: JACC review topic of the week. J Am Coll Cardiol 2024;83:1085–1099. doi: 10.1016/j.jacc.2024.01.010
- Takahashi K, Sasaki D, Yamashita M, Sakaue T, Enomoto D, Morioka H, et al. Amyloid deposit corresponds to technetium-99m-pyrophosphate accumulation in abdominal fat of patients with transthyretin cardiac amyloidosis. J Nucl Cardiol 2022;29:3126–3136. doi: 10.1007/s12350-021-02890-6
- Takahashi K, Hiratsuka Y, Iwamura T, Sasaki D, Yamamura N, Kitazawa S, et al. Technetium-99m-pyrophosphate imaging-based computed tomography-guided core-needle biopsy of internal oblique muscle in wild-type transthyretin cardiac amyloidosis. Amyloid 2024;31:12–21. doi: 10.1080/13506129.2023.2235881
- Takahashi K, Hiratsuka Y, Sasaki D, Sakaue T, Enomoto D, Morioka H, et al. 99mTc-pyrophosphate scintigraphy can image tracer uptake in skeletal trunk muscles of transthyretin cardiac amyloidosis. Clin Nucl Med 2023;48:18–24. doi: 10.1097/RLU.0000000000004397
- Takahashi K, Iwamura T, Hiratsuka Y, Sasaki D, Yamamura N, Ueda M, et al. A gluteus medius muscle biopsy to confirm amyloid transthyretin deposition in wild-type transthyretin cardiac amyloidosis: a report of two cases. Intern Med 2024;63:1575–1584. doi: 10.2169/internalmedicine.2742-23
- Rajappan K. Permanent pacemaker implantation technique: part I. Heart 2009;95;259–264. doi: 10.1136/hrt.2007.132753
- Takano R, Ueda N, Okada A, Matsumoto M, Ikeda Y, Hatakeyama K, et al. Fat biopsy from a pocket of cardiac implantable electronic device: an alternative diagnostic option for cardiac amyloidosis. HeartRhythm Case Rep 2022;8:554–557. doi: 10.1016/j.hrcr.2022.05.008
- Mvita Bakatubia C, Vergier R, Simeon M, Buila Bimbi N, Malka N, Lounaci K, et al. Thoracic fat pad biopsy in cardiac amyloidosis: diagnostic yield in an Afro-Caribbean population. J Clin Med 2025;14:1677. doi: 10.3390/jcm14051677
- Kitaoka H, Izumi C, Izumiya Y, Inomata T, Ueda M, Kubo T, et al. JCS 2020 guideline on diagnosis and treatment of cardiac amyloidosis. Circ J 2020;84:1610–1671. doi: 10.1253/circj.CJ-20-0110
- Takahashi K, Iwamura T, Hiratsuka Y, Sasaki D, Yamamura N, Ueda M, et al. Iatrogenic intramuscular hematoma of the oblique muscles as a complication of technetium-99m-labeled pyrophosphate imaging-based computed tomography-guided core-needle biopsy in a patient with wild-type transthyretin cardiac amyloidosis. Radiol Case Rep 2023;19:330–340. doi: 10.1016/j.radcr.2023.09.107