Impact of microvascular obstruction on the assessment of coronary flow reserve, index of microcirculatory resistance, and fractional flow reserve after ST-segment elevation myocardial infarction.

BACKGROUND: Invasive assessment of coronary physiology (IACP) offers important prognostic insights in ST-segment elevation myocardial infarction (STEMI) but the dynamics of coronary recovery are poorly understood. OBJECTIVES: This study sought to examine the evolution of coronary flow reserve (CFR), index of microcirculatory resistance (IMR), ratio of distal coronary pressure (Pd) to mean aortic pressure (Pa), and fractional flow reserve (FFR) in patients undergoing primary percutaneous coronary intervention (PPCI). METHODS: 82 patients with STEMI underwent IACP at PPCI. Repeat IACP was performed in 61 patients (74%) at day 1 and in 46 patients (56%) at 6 months. Contrast-enhanced cardiac magnetic resonance imaging (CMR) was performed in 45 patients (55%) at day 1 and in 41 patients (50%) at 6 months. Changes in IACP were compared between patients with and without microvascular obstruction (MVO) on CMR. RESULTS: MVO was present in 21 of 45 patients (47%). Patients with MVO had lower CFR at PPCI and day 1 (p < 0.05) and a trend toward higher IMR values (p = 0.07). At 6 months, CFR and IMR were not significantly different between the groups. Baseline flow and Pd/Pa remained stable over time but FFR reduced significantly between PPCI and 6 months (p = 0.008); this reduction was mainly observed in patients with MVO (p = 0.006) but not in those without MVO (p = 0.21). CONCLUSIONS: In PPCI-treated patients with STEMI, coronary microcirculation begins to recover within 24 h and recovery progresses further by 6 months. FFR significantly reduces from baseline to 6 months. The presence of MVO indicates a highly dysfunctional microcirculation.

Angiographic assessment of myocardial perfusion in Tako-Tsubo syndrome.

OBJECTIVES: To angiographically assess myocardial perfusion in patients with Tako-Tsubo syndrome (TTS) in comparison with control individuals and patients with ST-elevation myocardial infarction (STEMI). BACKGROUND: Coronary microvascular dysfunction has been proposed as the pathophysiological mechanism underlying TTS. METHODS: We retrospectively selected consecutive TTS patients showing typical left ventricular (LV) apical dysfunction admitted to our Department in the period 2007-2011 (n=25). We also enrolled an age and gender-matched control group showing normal coronary arteries (CTR, n=25), patients with STEMI undergoing primary percutaneous intervention with myocardial reperfusion (SR, n=25) or microvascular obstruction (SMVO, n=25). TIMI flow, TIMI frame count (TFC) and both qualitative and quantitative myocardial blush grade in LV apex were assessed. Specifically, myocardial perfusion was quantitatively evaluated using 'Quantitative Blush Evaluator' (QuBE), an open source software previously validated in the setting of STEMI. RESULTS: In TTS, TIMI flow on the LAD was significantly lower and TFC significantly higher compared to CTR and SR (p=0.008 for both), while it did not significantly differ compared to SMVO (p=0.06). In TTS, MBG was significantly lower than that in CTR and SR (p=0.001 for both), while it was significantly higher than that in SMVO (p<0.001). In TTS, QuBE score was significantly lower than that in CTR and SR (p=0.001 for both) and higher than in SMVO (p=0.02). CONCLUSIONS: Our data indicate that myocardial perfusion assessed during angiography is more impaired in patients with TTS than in patients with STEMI exhibiting myocardial reperfusion, while it is less impaired than in patients with STEMI exhibiting MVO.

Incidence, predictors and management of left main coronary artery stent restenosis: a comprehensive review in the era of drug-eluting stents.

International guidelines recommend surgical revascularisation for unprotected left main (ULM) coronary artery disease. The introduction of drug-eluting stents (DES) as an emergency therapy has resulted in increasing numbers of patients having stents placed in ULM. As a consequence, important data on the safety and long-term outcome of PCI for ULM have progressively accumulated over recent years, derived mainly from registries rather than prospective randomised trials. These studies indicate that restenosis of the ULM still represents the main predictor of clinical events following stenting. However, the observed incidence is highly variable amongst the published studies and there is little data about the clinical management of restenosis of stents placed in the ULM. In the present paper we review the available literature regarding ULM restenosis, identify its predictors and suggest an algorithm for optimal management.