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BACKGROUND: Coronary microvascular dysfunction (CMD) is an important contributor to angina syndromes. Recently, two distinct endotypes were identified using combined assessment of coronary flow reserve (CFR) and minimal microvascular resistance (MR), termed structural and functional CMD.AIMS: We aimed to assess the relevance of the combined assessment of CFR and MR in patients with angina and no obstructive coronary arteries.METHODS: Patients with chronic coronary syndromes (CCS) and non-obstructive coronary artery disease (fractional flow reserve [FFR] ≥0.80) were selected (N=1,102). Functional CMD was defined as abnormal CFR in combination with normal MR and structural CMD as abnormal CFR with abnormal MR. Clinical endpoints were the incidence of major adverse cardiac events (MACE) and target vessel failure (TVF) at 5-year follow-up.RESULTS: Abnormal CFR was associated with an increased risk of MACE and TVF at 5-year follow-up. Microvascular resistance parameters were not associated with MACE or TVF at 5-year follow-up. The risk of MACE and TVF at 5-year follow-up was similarly increased for patients with structural or functional CMD compared with patients with normal microvascular function. There were no differences between both endotypes (p=0.88 for MACE, and p=0.55 for TVF).CONCLUSIONS: Coronary microvascular dysfunction, identified by an impaired CFR, was unequivocally associated with increased MACE and TVF rates over a 5-year follow-up period. In contrast, impaired MR was not associated with 5-year adverse clinical events. Moreover, there was no significant difference in the risk of MACE and TVF between a low CFR accompanied by pathologically increased MR (structural CMD) or not (functional CMD).CLINICALTRIALS: gov: NCT04485234.

Long-term benefits of coronary stenosis treatment with an everolimus-eluting bioresorbable scaffold are unknown.This study sought to evaluate clinical and imaging outcomes 5 years after bioresorbable scaffold implantation.In the ABSORB multicenter, single-arm trial, 45 (B1) and 56 patients (B2) underwent coronary angiography, intravascular ultrasound (IVUS), and optical coherence tomography (OCT) at different times. At 5 years, 53 patients without target lesion revascularization underwent final imaging.Between 6 months/1 year and 5 years, angiographic luminal late loss remained unchanged (B1: 0.14 ± 19 mm vs. 0.13 ± 0.33 mm; p = 0.7953; B2: 0.23 ± 0.28 mm vs. 0.18 ± 0.32 mm; p = 0.5685). When patients with a target lesion revascularization were included, luminal late loss was 0.15 ± 0.20 mm versus 0.15 ± 0.24 mm (p = 0.8275) for B1 and 0.30 ± 0.37 mm versus 0.32 ± 0.48 mm (p = 0.8204) for B2. At 5 years, in-scaffold and -segment binary restenosis was 7.8% (5 of 64) and 12.5% (8 of 64). On IVUS, the minimum lumen area of B1 decreased from 5.23 ± 0.97 mm(2) at 6 months to 4.89 ± 1.81 mm(2) at 5 years (p = 0.04), but remained unchanged in B2 (4.95 ± 0.91 mm(2) at 1 year to 4.84 ± 1.28 mm(2) at 5 years; p = 0.5). At 5 years, struts were no longer discernable by OCT and IVUS. On OCT, the minimum lumen area in B1 decreased from 4.51 ± 1.28 mm(2) at 6 months to 3.65 ± 1.39 mm(2) at 5 years (p = 0.01), but remained unchanged in B2, 4.35 ± 1.09 mm(2) at 1 year and 4.12 ± 1.38 mm(2) at 5 years (p = 0.24). Overall, the 5-year major adverse cardiac event rate was 11.0%, without any scaffold thrombosis.At 5 years, bioresorbable scaffold implantation in a simple stenotic lesion resulted in stable lumen dimensions and low restenosis and major adverse cardiac event rates. (ABSORB Clinical Investigation, Cohort B [ABSORB B]; NCT00856856).

This study sought to describe the frequency and clinical impact of acute scaffold disruption and late strut discontinuity of the second-generation Absorb bioresorbable polymeric vascular scaffolds (Absorb BVS, Abbott Vascular, Santa Clara, California) in the ABSORB (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System in the Treatment of Patients With De Novo Native Coronary Artery Lesions) cohort B study by optical coherence tomography (OCT) post-procedure and at 6, 12, 24, and 36 months.Fully bioresorbable scaffolds are a novel approach to treatment for coronary narrowing that provides transient vessel support with drug delivery capability without the long-term limitations of metallic drug-eluting stents. However, a potential drawback of the bioresorbable scaffold is the potential for disruption of the strut network when overexpanded. Conversely, the structural discontinuity of the polymeric struts at a late stage is a biologically programmed fate of the scaffold during the course of bioresorption.The ABSORB cohort B trial is a multicenter single-arm trial assessing the safety and performance of the Absorb BVS in the treatment of 101 patients with de novo native coronary artery lesions. The current analysis included 51 patients with 143 OCT pullbacks who underwent OCT at baseline and follow-up. The presence of acute disruption or late discontinuities was diagnosed by the presence on OCT of stacked, overhung struts or isolated intraluminal struts disconnected from the expected circularity of the device.Of 51 patients with OCT imaging post-procedure, acute scaffold disruption was observed in 2 patients (3.9%), which could be related to overexpansion of the scaffold at the time of implantation. One patient had a target lesion revascularization that was presumably related to the disruption. Of 49 patients without acute disruption, late discontinuities were observed in 21 patients. There were no major adverse cardiac events associated with this finding except for 1 patient who had a non-ischemia-driven target lesion revascularization.Acute scaffold disruption is a rare iatrogenic phenomenon that has been anecdotally associated with anginal symptoms, whereas late strut discontinuity is observed in approximately 40% of patients and could be viewed as a serendipitous OCT finding of a normal bioresorption process without clinical implications. (ABSORB Clinical Investigation, Cohort B [ABSORB B]; NCT00856856).

To investigate the impact of pre-operative autonomic balance and atrial ectopic activity on the risk of atrial fibrillation or flutter after aorto-coronary artery bypass surgery 24-hour Holter monitoring was analyzed in 102 patients before coronary artery bypass grafting. Index for vagal tone was calculated as % successive RR-interval differences6%. Twenty-nine (28%) of the 102 patients developed atrial fibrillation or flutter. Independent predictors (90% confidence interval) of postoperative atrial fibrillation or flutter were identified by logistic regression analysis: the independent predictors were older age, relative risk 1.07/year (1.02-1.12), vagal index10%, relative risk 4.50 (1.40-14.5),or= 10 ectopic supraventricular beats/24 hour, relative risk 3.03 (1.05-8.72), and one or more event of non-sustained supraventricular tachycardia, relative risk 3.02 (1.11-8.22). Thus, age of the patient, attenuated preoperative cardiac vagal modulation, ectopic supraventricular beats, and paroxysmal non-sustained supraventricular tachycardia are independent risk factors for the development of atrial fibrillation or flutter after coronary artery bypass surgery.

Chronic atrial fibrillation is by definition always preceded by paroxysmal atrial fibrillation. The electropathophysiological mechanisms underlying paroxysmal atrial fibrillation are reviewed: atrial electrophysiological inhomogeneity, atrial ectopic activity, and cardiac autonomic dysfunction. Safe and effective interventions that prevent the progression from paroxysmal into chronic atrial fibrillation have not yet been developed. Such developments should be given high priority, as the consequences of chronic atrial fibrillation--stroke and heart failure--are unacceptable.