Coronary endothelial function and spontaneous coronary artery dissection.

OBJECTIVES: To investigate the role of endothelial function in patients with previous spontaneous coronary artery dissection. BACKGROUND: Mechanisms underlying spontaneous coronary artery dissection, including a possible contribution from endothelial dysfunction, remain poorly understood. METHODS: This was a single center, retrospective study of patients with a prior spontaneous coronary artery dissection episode who underwent invasive endothelial function testing in the cardiac catheterization laboratory for evaluation of recurrent chest pain. Coronary epicardial and microvascular responses to acetylcholine, adenosine, and nitroglycerine were assessed. Findings were compared to a reference group of normal controls (n=232). RESULTS: A total of 10 patients with prior angiographically confirmed spontaneous coronary artery dissection were referred for coronary endothelial function testing. The median coronary flow reserve was 2.8 (interquartile range (IQR) 2.3, 3.6). The median change in coronary diameter with acetylcholine was -0.9% (IQR -23.9, 4.2). The median increase in peak coronary blood flow following acetylcholine administration was 91.4% (IQR 9.1, 105.7), which was similar to the response observed in a reference group of patients (median age 51 years, 96% women) from our laboratory with normal microvascular responses to acetylcholine: 107.4% (IQR 75.5, 165.7; P=0.20). Four patients (40%) had an abnormal microvascular response to acetylcholine, with less than a 50% increase in coronary blood flow, and all but one patient had left anterior descending artery or multivessel spontaneous coronary artery dissection. CONCLUSION: Coronary epicardial and microvascular vasomotor dysfunction is not a predominant feature of spontaneous coronary artery dissection. Endothelial dysfunction is not implicated as the principal underlying mechanism.

Non-atherosclerotic causes of acute coronary syndromes.

Atherosclerosis and plaque disruption have a central pathological role in the majority of patients who present with an acute coronary syndrome (ACS), but non-atherosclerotic processes are also important contributors to a substantial number of ACS events and require different diagnostic and therapeutic strategies. In the absence of obstructive coronary artery disease, intravascular imaging techniques might be needed to delineate the underlying aetiology, together with a high index of suspicion for other important causes of ACS. In this Review, we discuss five non-atherosclerotic causes of ACS, including spontaneous coronary artery dissection, coronary artery embolism, vasospasm, myocardial bridging and stress-induced cardiomyopathy (Takotsubo syndrome). Important diagnostic findings, management strategies and prognostic data for these non-atherosclerotic mechanisms of ACS are reviewed.

Early Natural History of Spontaneous Coronary Artery Dissection.

BACKGROUND: Risks and mechanisms of extension of conservatively managed spontaneous coronary artery dissection (SCAD) remain incompletely understood. Study objectives were to (1) evaluate mechanisms of early SCAD evolution through serial angiographic analysis, and (2) determine predictors of early SCAD progression. METHODS AND RESULTS: Retrospective registry study of patients with SCAD managed with an initial conservative strategy (n=240). Patients who experienced significant SCAD progression within 14 days, defined as clinical worsening plus new critical coronary obstruction on repeat angiography, were compared with remaining controls. A total of 42 of 240 (17.5%) experienced significant SCAD progression after index conservative approach; 91% by day 6. Isolated intramural hematoma (IMH) at baseline (no intimal dissection) was observed more frequently in those experiencing progression compared with controls (69.1% versus 44.4%; P=0.004). Multivariable predictors of SCAD progression included lesion severity, multivessel involvement, and isolated IMH. To investigate mechanisms of SCAD evolution, all repeat angiograms ≤14 days were compared with corresponding baselines (n=82 patient angiogram pairs). Of those with isolated IMH at baseline, 20% developed intimal dissection at repeat study. IMH was associated with greater longitudinal lesion extension (11.5 versus 2.8 mm; P=0.01), worsening Thrombolysis in Myocardial Infarction flow (-0.8 versus 0.1; P=0.003), and a nonsignificant lower rate of angiographic improvement (20.0% versus 31.3%; P=0.16) compared with the group with baseline intimal dissection. Optical coherence tomography subgroup analysis (n=17) indicated intimo-medial thickness to be lowest at the midpoint of IMH. CONCLUSIONS: Conservatively managed SCAD carries a 1:6 hazard for serious deterioration within 6 days. The risk was higher in those with isolated IMH at baseline. IMH often precedes development of intimal dissection, which has implications for mechanisms of SCAD.

Techniques and outcomes of paravalvular leak repair after transcatheter aortic valve replacement.

OBJECTIVES: To investigate the feasibility, procedural success, and outcomes of paravalvular leak (PVL) closure in patients with prior transcatheter aortic valve replacement (TAVR). BACKGROUND: PVL after TAVR is associated with adverse patient outcomes and increased mortality. Percutaneous PVL closure has emerged as a therapeutic strategy for addressing this issue, but data for transcatheter PVL repair after TAVR remains limited. METHODS: This is a single center retrospective review of PVL closure after TAVR. Patients with balloon-expandable or self-expanding prostheses were included. Baseline patient demographics, procedural characteristics, complications, and clinical outcomes were reviewed. RESULTS: A total of 18 patients with clinically significant PVL after TAVR referred for PVL closure were identified during the study period. Procedural success resulting in successful transcatheter occluder plug delivery was 78% (14 cases). Balloon postdilatation (2/4) and valve-in-valve (2/4) were used effectively in the remaining patients after an unsuccessful PVL closure attempt. PVL grading by echocardiography decreased from moderate or severe to < moderate in 13 patients (72%). Adverse events including cardiac tamponade and acute kidney injury occurred in 1 case each. One-month all-cause mortality was 11%. CONCLUSION: In selected patients, percutaneous PVL repair following TAVR is feasible and effective for both balloon-expandable and self-expanding prostheses. Most patients undergoing PVL closure after TAVR require a single occluder plug placement for reduction in PVL to mild or less.

Experience and complications associated with use of guide extension catheters in percutaneous coronary intervention.

OBJECTIVES: To investigate the utility and safety of the GuideLiner "mother-and-child" catheter system during transradial and transfemoral percutaneous coronary intervention (PCI). BACKGROUND: In patients with complex coronary anatomy, stent delivery can be challenging and result in procedural failure and complications. The GuideLiner is a coaxial guide extension system designed to enable deep vessel engagement and facilitate device delivery. The purpose of this study was to evaluate procedural success and safety in a series of GuideLiner-facilitated PCI. METHODS: Single center retrospective study of PCI utilizing the GuideLiner catheter between February 2010 and October 2014. Patients who underwent PCI without GuideLiner use during the same time period were used as controls for comparison. RESULTS: A total of 363 cases of GuideLiner-facilitated PCI were identified from 6,088 unique PCI procedures performed during this same time period. Patients in the GuideLiner group were older (mean age 71.5 vs. 67.8, P < 0.001) and had more multivessel disease (72% vs. 63%, P = 0.001) compared with controls. Type C lesions were present in 78% of GuideLiner cases. Procedural success resulting in successful device delivery with the GuideLiner catheter was 80.2%. Stent deformation associated with GuideLiner use occurred in 2.2% (8/363), with the incidence of this complication decreasing over device iterations. Coronary dissection attributed to GuideLiner occurred in 3.3% (12/363) and became less frequent over the study period. CONCLUSIONS: In this consecutive series of GuideLiner supported PCI, the guide extension system enabled procedural success in the majority. A decline in device-associated complications over time may be attributed to operator learning curve, patient selection, and improvement in catheter design. © 2015 Wiley Periodicals, Inc.