Angiography-derived index of microvascular resistance in takotsubo syndrome

Abstract

Coronary microvascular dysfunction (CMD) has been proposed as a key driver in the etiopathogenesis of Takotsubo syndrome (TTS), likely related to an “adrenergic storm” upon a susceptible microvascular circulation. The aim of our manuscript was to assess CMD in patients with TTS through the computation of the angiography-derived index of microcirculatory resistance (IMR) and its correlation with clinical presentation. Coronary angiograms of 41 consecutive TTS patients were retrospectively analyzed to derive angiography-based indices of CMD. Three indices (NH-IMRangio, AngioIMR and A-IMR) were calculated based on quantitative flow ratio. CMD was defined as an IMRangio value ≥ 25 units. The correlation between CMD and clinical presentation was then assessed. Median age was 76 years, 85.7% were women and mean left ventricular ejection fraction (LVEF) at first echocardiogram was 41.2%. Angiography-derived IMR was higher in left anterior descending artery (LAD) than circumflex and right coronary artery with either NH-IMRangio (53.9 ± 19.8 vs 35.8 ± 15.4 vs 40.8 ± 18.5, p-value < 0.001), AngioIMR (47.2 ± 17.3 vs 31.8 ± 12.2 vs 37.3 ± 13.7, p-value < 0.001) or A-IMR (52.7 ± 19 vs 36.1 ± 14.1 vs 41.8 ± 16.1, p-value < 0.001). All patients presented CMD with angiography-derived IMR ≥ 25 in at least one territory with each formula. Angiography-derived IMR in LAD territory was significantly higher in patients presenting with LVEF impairment (≤ 40%) than in those with preserved ventricular global function (NH-IMRangio: 59.3 ± 18.1 vs 46.3 ± 16.0 p-value = 0.030; AngioIMR: 52.9 ± 17.8 vs 41.4 ± 14.2, p-value = 0.037; A-IMR: 59.2 ± 18.6 vs 46.3 ± 17.0, p-value = 0.035). CMD assessed with angiography-derived IMR is a common finding in TTS and it is inversely correlated with LV function. The available formulas have a substantial superimposable diagnostic performance in assessing coronary microvascular function.

In Vivo Validation of a Novel Computational Approach to Assess Microcirculatory Resistance Based on a Single Angiographic View

“…In the setting of heart transplantation, on top of its diagnostic and prognostic relevance, CMD assessment enables the tailoring of medical treatment, with reversibility of CMD after the implementation of the pharmacological treatment scheme [8,9,27]. Moreover, CMD was found to predict left ventricular dysfunction and a higher risk of adverse events in patients presenting with Takotsubo syndrome [28,29].…”

Cardioprotective and Antianginal Efficacy of Nicorandil: A Comprehensive Review

“…93–95 In addition, CMD has been found to be consistently present during the acute phase of Takotsubo. 88,96–98 Moreover, degree of CMD parallels the degree of left ventricular dysfunction, follows a similar pattern of improvement as left ventricular dysfunction following the acute phase, and has been shown to independently predict outcomes. 97,99 Given these findings, NCO has been investigated in patients with first episode as well as recurrent Takotsubo, albeit the evidence remains anecdotal.…”

Takotsubo Syndrome and Coronary Artery Disease: Which Came First—The Chicken or the Egg?

“…In a recent study, Solberg et al reported that IMR values above 25, indicating microvascular dysfunction, were found in nearly a third of TTS patients in the acute phase [130]. Similarly, Castaldi et al demonstrated that CMD, as measured by angiography-derived IMR, was inversely linked with LV function and was a common finding in TTS [131]. Interestingly, there is a correlation between an increase in LV function and a temporal improvement in microvascular resistance [129].…”