Unsuspected amyloidosis and cardiac arrest following mitral valve replacement

Cardiac amyloidosis in non-transplant cardiac surgery

Cardiac amyloidosis is a rare infiltrative cardiomyopathy that portends a poor prognosis. There is a growing recognition of co-existent aortic valve stenosis and transthyretin cardiac amyloidosis, with some studies suggesting that dual pathology may be associated increased risk of complication and mortality during surgical intervention. This review aims to evaluate the available literature on non-transplant cardiac surgical interventions in patients with cardiac amyloidosis, with particular focus on diagnosis, high surgical risk and areas of uncertainty that require further research.

Isolated atrial amyloid: a potential contributor to morbidity and mortality following cardiac surgery

OBJECTIVES

Diffuse cardiac amyloidosis is a significant diagnosis with a poor prognosis. Isolated atrial amyloidosis (IAA) is the most common form of cardiac amyloidosis caused by accumulation of alpha-atrial natriuretic peptide. IAA has been associated with dysrhythmia, but otherwise remains a poorly characterized condition. The impact of incidental IAA on postoperative outcome following cardiac surgery has not previously been reported. The purpose of this study was to examine the impact of isolated atrial amyloid on patient outcomes following cardiac surgery.

METHODS

A retrospective analysis was performed of all patients having excision of the left atrial appendage during cardiac surgery at our centre over a 5-year period. Patients with histological evidence of IAA were compared to patients without this diagnosis. IAA was diagnosed by immunohistochemistry for atrial natriuretic peptide.

RESULTS

A total of 167 patients underwent left atrial appendage excision and of these 26 (15.6%) were found to have IAA. Preoperative characteristics were similar between the 2 groups. A significantly greater proportion of patients with IAA experienced dysrhythmia requiring implantation of a permanent pacemaker (23.1% vs 7.8%, P = 0.03). There was also a significantly elevated incidence of perioperative death in the IAA group (11.5% vs 1.4%, P = 0.03) and inferior 1-year survival (84.6% vs 96.5%, P = 0.02).

CONCLUSIONS

The presence of IAA may be associated with inferior outcomes following cardiac surgery, with increased morbidity in the early postoperative period and inferior long-term survival. Knowledge of the diagnosis preoperatively may facilitate management of patients.

An unexpected mortality following cardiac surgery: a post-mortem diagnosis of cardiac amyloidosis

Amyloidosis is a rare systemic disease that is notoriously difficult to diagnose early. Cardiac involvement is associated with a poor prognosis. We present the case of a 72-year-old gentleman who underwent elective coronary artery bypass grafting and mitral valve repair. While initially making a good post-operative recovery, a sudden deterioration on post-operative day 3 led to an unexpected mortality. Post-mortem examination demonstrated previously undiagnosed severe systemic amyloidosis, which particularly affected his heart, due to underlying multiple myeloma. It is important to emphasise that due to the absence of the typical findings on routine pre-operative investigations suggestive of cardiac amyloidosis in this patient, cardiac surgeons should be aware that symptoms inconsistent with angiography findings should prompt consideration of amyloidosis. Diagnostic tools including cardiac MRI and ultimately endomyocardial biopsy could then facilitate earlier recognition of this enigmatic disease process.

[Cardiac amyloidosis. General review]

Cardiac amyloidosis, most often of AL type, is a non-exceptional disease as it represents 5 to 10% of non-ischemic cardiomyopathies. It realizes typically a restrictive cardiomyopathy. Nevertheless the wide diversity of possible presentation makes it a "big shammer" which must be evoked in front of every unexplained cardiopathy after the age of forty. If some associated manifestations can rapidly suggest the diagnosis, as a peripheric neuropathy especially a carpal tunnel syndrome or palpebral ecchymosis, cardiac involvement can also evolve in an apparently isolated way. The most suggestive paraclinic elements for the diagnosis are, in one hand, the increased myocardial echogenicity with a "granular sparkling" appearance seen throughout all walls of the left ventricle and, in the other hand, the association of a thickened left ventricle and a low voltage (electrocardiogram could also show pseudo-infarct Q waves). In front of such aspects, the proof of amyloidosis is brought by an extra-cardiac biopsy or by scintigraphy with labelled serum amyloid P component, so that the indications of endomyocardial biopsy are very limited today. The identification of the amyloid nature of a cardiopathy has an direct therapeutic implication: it contra-indicates the use of digitalis, calcium channel blockers and beta-blockers. The treatment of AL amyloidosis (chemotherapy with alkylant agents) remains very unsatisfactory especially in the cardiac involvement which is the most frequent cause of death (in AL amyloidosis). Last, cardiac amyloidosis is a bad indication for transplantation which results are burden by rapid progression of deposits especially in the gastro-intestinal tract and the nervous system.