Acute, repetitive and chronic Takotsubo syndrome in patients with chronic kidney disease: Sympathetic reno-cardial syndrome

Autonomic neurocardiogenic syndrome is stonewalled by the universal definition of myocardial infarction

Myocardial infarction (MI) is defined as myocardial cell death due to prolonged myocardial ischemia. Clinically, troponin rise and/or fall have become the “defining feature of MI” according to the universal definition of MI (UD-MI). Takotsubo syndrome (TS) and TS-related disease conditions also cause troponin elevation with typical rise and/or fall pattern but through a mechanism other than coronary ischemia. By strict application of the clinical diagnostic criteria for type-1 MI, type-2 MI, type-3 MI, and MI with non-obstructive coronary arteries according to the UD-MI including the fourth one published recently, TS and most of the 26 other causes of troponin elevation mentioned in the fourth UD-MI may erroneously be classified as MI. The existing evidence argues for the case that TS by itself is not a MI. Hyper-activation of the autonomic-sympathetic nervous system including local cardiac sympathetic hyper-activation and disruption with nor-epinephrine churn and spillover is the most probable cause of TS. This autonomic neuro-cardiogenic (ANCA) mechanism results in myocardial “cramp” (stunning), the severity and duration of which depend on the degree of the sympathetic-hyperactivation and nor-epinephrine spillover. The myocardial cramp may squeeze the cytosolic free troponin pools causing mild to moderate troponin elevation in TS and TS-related disease conditions. This ANCA syndrome, which has hitherto been enveloped by the UD-MI over more than one decade, may occur in acute, recurrent, and chronic forms. In this critical review, the controversies of UD-MI, evidence for ANCA syndrome, and a hypothetical mechanism for the troponin elevation in ANCA syndrome are provided.

Renal dysfunction indicative of outcomes in hospitalized patients with takotsubo syndrome

Background:

Left ventricular dysfunction as part of takotsubo syndrome is reversible, and the long-term prognosis appears favorable. However, life-threatening complications are not uncommon during the acute phase, and it remains unclear whether renal dysfunction is a factor in complications suffered by hospitalized patients with takotsubo syndrome. The present study was conducted to investigate the implications of renal dysfunction in this setting.

Methods:

Data from 61 consecutive patients (male, 21; female, 40) diagnosed with takotsubo syndrome at our hospital between years 2010 and 2016 were evaluated retrospectively. In-hospital complications by definition were all-cause deaths and severe pump failure (Killip class ≥III).

Results:

Overall, 30 patients (49%) developed renal dysfunction. In the 32 patients (52%) who suffered in-hospital complications (mortality, 10; severe pump failure, 22), estimated glomerular filtration rate (eGFR) was significantly lower by comparison (51.3±29.8 vs. 69.5±29.0; p=0.019). Low eGFR (<30 ml/min per 1.73m2) proved independently predictive of in-hospital complications (hazard ratio =2.84, 95% confidence interval: 1.20–6.69) in multivariate Cox hazard analysis, also showing a significant association with peak event rate of Kaplan–Meier curve (log-rank test, p=0.0073). Similarly, patients with chronic kidney disease were at significantly greater risk of in-hospital complications (hazard ratio=2.49, 95% confidence interval: 1.01–5.98), relative to non-compromised counterparts (eGFR >60 ml/min per 1.73m2).

Conclusion:

Renal dysfunction is a simple but useful means of predicting complications in hospitalized patients with takotsubo syndrome, especially those with chronic kidney disease.