A propensity matched analysis of cardiac operation in patients with cardiac amyloidosis

A. Chauhan¹, K. L.. Greason², J. Stulak¹, R. Daly¹, J. Crestanello¹, H. V. Schaff^1
1Mayo Clinic, Rochester, Minnesota ²Mayo Medical Center, Rochester, Minnesota

Purpose: Cardiac amyloidosis is rare, and certain subtypes are linked to poor prognosis. There are scarce data on the outcomes of routine cardiac procedures in such patients. The purpose of the present study was to assess the impact of amyloidosis on early and late outcomes of patients undergoing routine cardiac procedures.

Methods: This was a single center retrospective case-control study of patients with cardiac amyloidosis (diagnosed either pre- or post-operatively on histopathology) undergoing cardiac surgery at our hospital from 1/1/1998 to 12/31/2022. Heart transplantation and ventricular assist implantation were excluded. Controls were patients without known cardiac amyloidosis. The 2 groups were propensity matched on baseline patient characteristics, echocardiographic findings, and type of operation. The primary outcome was overall survival, and secondary outcomes included operative and postoperative complications. Comparisons between groups were made using Kruskal-Wallis tests or Chi Square tests, as appropriate. For the primary outcome, unadjusted survival curves were constructed using the Kaplan-Meier estimator. Statistical significance was defined as P less than .05.

Results: We identified 42 patients with cardiac amyloidosis (AG group) operated over last 25 years. They were matched with 168 controls (CON group). Cardiac amyloidosis was diagnosed preoperatively in 11 patients (45.5% ATTR and 54.5% AL subtype) and incidentally on intraoperative biopsy in 31 (93.5% ATTR and 6.5% AANF subtype). Aortic valve operation (n= 19, 45%) and septal myectomy (n=16, 38%) were the most common operations. Median LV ejection fraction was 62.5% in AG group (versus 64% CONS). Cardiopulmonary bypass (P=0.253) and cross clamp (P=0.063) times were similar in the two groups. Mechanical circulatory support in the amyloidosis group included ECMO in 1 (2.4%) patient (versus n=0 CON; P=0.200) and intra-aortic balloon pump use in 3 (7.1%) patients (versus n=12 [7.1%] CON; P=1.000). Length of intensive care and hospital stay were similar in the two groups. Complication rates were similar in the groups with respect to atrial fibrillation, shock, low cardiac output syndrome, pacemaker insertion, stoke, operation for bleeding, sternal infection, renal failure, and pneumonia. There were no operative deaths or deaths within 30 days of operation. Estimated survival in the amyloidosis group was 92.7% for 1 year (vs 93.1% CON) and 55.2% for 5 years (vs 65.1% CON; P=0.036).

Conclusion: Procedural outcomes in patients with cardiac amyloidosis undergoing cardiac surgery are favorable, and overall survival is comparable to unaffected patients. Diagnosis of amyloidosis is not a contraindication to cardiac surgery in patients without amyloid-related restrictive cardiomyopathy.

Identify the source of the funding for this research project: No funding was required for this research.