Citations

SummaryCoronary endothelial‐dependent microvascular dysfunction, an early reversible stage of coronary artery disease (CAD), is associated with poor clinical outcome. The current study investigated whether coronary artery distensibility index (CDI) is associated with: (i) coronary endothelial‐dependent microvascular dysfunction and (ii) vulnerable plaque composition among subjects with non‐obstructive CAD. Seventy‐four subjects with non‐obstructive CAD (luminal stenosis <30%) were studied. In 20 subjects with and without coronary endothelial‐dependent microvascular dysfunction, coronary flow reserve (CFR) of target segment during intracoronary (IC) infusion of acetylcholine (Ach) and bolus injection of adenosine as well as CDI at rest of corresponding target segment were measured. In 54 subjects, plaque compositions and CDI at rest of 154 non‐obstructive coronary segments as well as proximal segment without disease were measured by intravascular ultrasound (IVUS). CDI was defined as: [(Early‐diastolic cross‐sectional‐area (CSA) – End‐diastolic CSA of target segment)/(end‐diastolic CSA of target segment × coronary‐pulse‐pressure) × 103]. There is a direct association between endothelial dysfunction and impaired CDI of a coronary segment both in the given coronary segment and corresponding microvessels in which a strong agreement between CDI and CFR Ach (r2 = 0·85, P = 0·0001) was observed. Multivariable regression‐analysis showed that CDI was an independent predictor of the vulnerable plaque characteristics. The risk of impaired CDI was 125% higher in segments with necrotic core and 60% higher in segments with fibrofatty components as compared to normal segments (P = 0·001). In conclusions, the current study reveals that impaired CDI is an endothelial‐dependent process of both given coronary segment and corresponding microvessels and is associated with vulnerable plaque composition.

Background— Spontaneous coronary artery dissection (SCAD) is a nonatherosclerotic acute coronary syndrome for which optimal management remains undefined. Methods and Results— We performed a retrospective study of 189 patients presenting with a first SCAD episode. We evaluated outcomes according to initial management: (1) revascularization versus conservative therapy and (2) percutaneous coronary intervention (PCI) versus conservative therapy stratified by vessel flow at presentation. Demographics were similar in revascularization versus conservative (mean age, 44±9 years; women 92% both groups), but vessel occlusion was more frequent in revascularization (44/95 versus 18/94). There was 1 in-hospital death (revascularization) and 1 late death (conservative). Procedural failure rate was 53% in those managed with PCI. In the subgroup of patients presenting with preserved vessel flow, rates of PCI failure were similarly high (50%), and 6 (13%) required emergency coronary artery bypass grafting. In the conservative group, 85 of 94 (90%) had an uneventful in-hospital course, but 9 (10%) experienced early SCAD progression requiring revascularization. Kaplan–Meier estimated 5-year rates of target vessel revascularization and recurrent SCAD were no different in revascularization versus conservative therapy (30% versus 19%; P =0.06 and 23% versus 31%; P =0.7). Conclusions— PCI for SCAD is associated with high rates of technical failure even in those presenting with preserved vessel flow and does not protect against target vessel revascularization or recurrent SCAD. A strategy of conservative management with prolonged observation may be preferable.

Objective— Endothelial dysfunction is an early manifestation of atherosclerosis. Inflammation and vasa vasorum play a pivotal role in the pathophysiology of plaque initiation, development, and complications. Optical coherence tomography allows high-resolution imaging of tissue microstructure. Therefore, the aim of this study was to test the hypothesis that segments with endothelial dysfunction show macrophages and vasa vasorum in patients with early coronary artery disease. Approach and Results— Optical coherence tomography images were obtained from 40 patients with mild coronary atherosclerosis who underwent coronary endothelial function assessment. Optical coherence tomography findings, including macrophages and microchannels, were evaluated in 76 coronary segments corresponding to those in endothelial response to acetylcholine. Coronary artery diameter change in response to acetylcholine was more severe in segments showing macrophages (−17.7±14.7% versus −6.3±13.9%; P <0.01) and microchannels (−15.9±15.9% versus −6.4±13.5%; P <0.01) than those without. There were increasing trends of the prevalence of macrophages and microchannels with endothelial dysfunction as stratified by quartiles of coronary artery diameter change ( P <0.01 and P =0.02 for trend, respectively). In particular, segments with both macrophages and microchannels (n=12) tended to have worse endothelial function than those with macrophages alone (n=15) and microchannels alone (n=15; −22.1±14.6% versus −10.9±15.6% and −10.9±15.6%; P =0.07 and P =0.06, respectively). Conclusions— Epicardial endothelial dysfunction was associated with optical coherence tomography –identified macrophages and microchannels in mild coronary atherosclerosis. The current study further supports the role of inflammation and vasa vasorum proliferation in the early stage of coronary atherosclerosis.

Background— Spontaneous coronary artery dissection (SCAD) is an increasingly recognized nonatherosclerotic cause of acute coronary syndrome. The angiographic characteristics of SCAD are largely undetermined. The goal of this study was to determine the prevalence of coronary tortuosity in SCAD and whether it may be implicated in the disease. Methods and Results— Patients with confirmed SCAD (n=246; 45.3±8.9 years; 96% women) and 313 control patients without SCAD or coronary artery disease who underwent coronary angiography were included in this case–control study. Angiograms were reviewed for coronary tortuosity and assigned a tortuosity score. Tortuosity was common in patients presenting with their first SCAD event (78% versus 17% in controls; P <0.0001; tortuosity score, 4.41±1.73 versus 2.33±1.49 in controls; P <0.0001) despite a low prevalence of hypertension (34%). Recurrent SCAD (n=40) occurred within segments of tortuosity in 80% of cases. Severe tortuosity (≥2 consecutive curvatures ≥180°) was associated with a higher risk of recurrent SCAD (hazard ratio, 3.29; 95% confidence interval, 0.99–8.29; P =0.05). Tortuosity score >5 was associated with a trend toward higher risk of recurrent SCAD ( P =0.16). Prespecified angiographic markers of tortuosity including corkscrew appearance and multivessel symmetrical tortuosity were associated with extracoronary vasculopathy including fibromuscular dysplasia ( P <0.05 for both). Conclusions— Coronary artery tortuosity is highly prevalent in the SCAD population and is associated with recurrent SCAD. Recurrent SCAD most often occurs within segments of tortuosity. Angiographic features of SCAD are associated with extracoronary vasculopathy, including fibromuscular dysplasia. These findings suggest that coronary tortuosity may serve as a marker or potential mechanism for SCAD.

Background Cardiac allograft vasculopathy is the leading cause of graft failure and death in heart transplant ( HT x) recipients; however, the association between the etiology of heart failure (ischemic cardiomyopathy [ ICM ] or non‐ ICM ) that led to HT x and progression of c ardiac allograft vasculopathy , and adverse events after HT x has not been explored. Methods and Results We retrospectively included 165 HT x patients, who were followed‐up with at least 2 virtual histology–intravascular ultrasound examinations after HT x, and grouped them as ICM (n=46) or non‐ ICM (n=119). Coronary artery plaque volume was analyzed using virtual histology–intravascular ultrasound, and cardiovascular event data—a composite of myocardial infarction, hospitalization for heart failure and arrhythmia, revascularization, retransplantation, and death including cardiovascular death—were collected from the medical records of all study subjects. ICM patients had significantly higher plaque volume at both first ( P =0.040) and follow‐up ( P =0.015) intravascular ultrasound examinations. After multivariate adjustment for traditional coronary risk factors, ICM was significantly associated with plaque progression (odds ratio 3.10; CI 1.17 to 9.36; P =0.023). Ten‐year cardiovascular event‐free survival was 50% in ICM patients compared with 84% in non‐ ICM patients (log‐rank test P =0.003). In multivariate Cox proportional hazard analysis, ICM was significantly associated with a higher event rate after HT x (hazard ratio 2.02; 95% CI 1.01 to 4.00; P =0.048). Conclusion Our study demonstrates that ischemic etiology of cardiomyopathy prior to HT x may be independently associated with plaque progression and higher event rate after HT x.

Endothelial progenitor cells (EPCs) participate in renal repair, but their number and function may be impaired by exposure to cardiovascular risk factors. The number of circulating EPCs is decreased in essential and renovascular hypertensive patients, but the effects of hypertension on EPC function are incompletely understood. We hypothesized that EPC function was preserved under well-controlled conditions in treated hypertensive patients. Patients with atherosclerotic renal artery stenosis (ARAS; n=22) or essential hypertension (n=24) were studied during controlled sodium intake and antihypertensive regimen. Late-outgrowth EPCs were isolated from the inferior vena cava (IVC) and renal vein blood of ARAS and essential hypertension patients and a peripheral vein of matched normotensive controls (n=18). The angiogenic function of EPCs was assessed in vitro, and multidetector computed tomography was used to measure single-kidney hemodynamics and function in ARAS and essential hypertension patients. Inflammatory biomarkers and EPC homing signal levels and renal release were calculated. Inferior vena cava and renal vein–obtained EPC function were similar in ARAS and essential hypertension patients and comparable to that in normal controls (tube length, 171.86±16.846, 191.09±14.222, 174.925±19.774 μm, respectively). Function of renal vein–obtained EPCs directly correlated with stenotic kidney glomerular filtration rate, EPC homing factors, and anti-inflammatory mediator levels in ARAS patients. Therefore, EPC function was relatively preserved in ARAS patients, although it directly correlated with renal function. Adequate EPC function supports the feasibility of using autologous EPCs as a therapeutic option in essential and renovascular hypertensive patients. Homing signals and inflammatory mediators may potentially regulate EPC angiogenic function.

Renovascular hypertension alters cardiac structure and function. Autophagy is activated during left ventricular hypertrophy and linked to adverse cardiac function. The angiotensin II receptor blocker, valsartan, lowers blood pressure and is cardioprotective, but whether it modulates autophagy in the myocardium is unclear. We hypothesized that valsartan would alleviate autophagy and improve left ventricular myocardial mitochondrial turnover in swine renovascular hypertension. Domestic pigs were randomized to control, unilateral renovascular hypertension, and renovascular hypertension treated with valsartan (320 mg/d) or conventional triple therapy (reserpine+hydralazine+hydrochlorothiazide) for 4 weeks after 6 weeks of renovascular hypertension (n=7 each group). Left ventricular remodeling, function, and myocardial oxygenation and microcirculation were assessed by multidetector computer tomography, blood oxygen level–dependent MRI, and microcomputer tomography. Myocardial autophagy, markers for mitochondrial degradation and biogenesis, and mitochondrial respiratory-chain proteins were examined ex vivo. Renovascular hypertension induced left ventricular hypertrophy and myocardial hypoxia, enhanced cellular autophagy and mitochondrial degradation, and suppressed mitochondrial biogenesis. Valsartan and triple therapy similarly decreased blood pressure, but valsartan solely alleviated left ventricular hypertrophy, ameliorated myocardial autophagy and mitophagy, and increased mitochondrial biogenesis. In contrast, triple therapy only slightly attenuated autophagy and preserved mitochondrial proteins, but elicited no improvement in mitophagy. These data suggest a novel potential role of valsartan in modulating myocardial autophagy and mitochondrial turnover in renovascular hypertension–induced hypertensive heart disease, which may possibly bolster cardiac repair via a blood pressure–independent manner.