Best, Patricia J.M.

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.

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— High sensitivity C-reactive protein (hsCRP) has been identified as a predictor of adverse cardiovascular outcomes. Whether hsCRP is a useful biomarker for risk stratification in contemporary percutaneous coronary intervention remains unknown. Methods and Results— We conducted a prospective study among 513 patients undergoing non-emergency percutaneous coronary intervention and examined the relationship between pre- and postprocedural hsCRP levels and outcomes. The patients were divided according to the median preprocedural hsCRP level (0.3 mg/dL). Patients with high hsCRP had significantly more adverse clinical characteristics. Preprocedural hsCRP level was an independent predictor of periprocedural myocardial infarction (odds ratio per doubling of hsCRP 1.15 [95% confidence interval, 1.01–1.31]; P =0.038). Unadjusted mortality (29.7% versus 9.9%; P <0.001) and the combined end point of death or myocardial infarction (36.5% versus 16.0%, P <0.001) during a follow-up of 5 years were markedly greater in patients with high preprocedural hsCRP. Similar relationships existed for postprocedural hsCRP. However, after multivariable adjustment, neither preprocedural hsCRP levels (hazard ratio per doubling 0.96 [0.92, 1.00]; P =0.066) nor postprocedural hsCRP levels (hazard ratio 0.98 [0.94, 1.02]; P =0.27) were significantly associated with mortality. Conclusions— High hsCRP is associated with a greater independent risk of periprocedural myocardial infarction, as defined by the universal definition, but is not an independent determinant of mortality after percutaneous coronary intervention. Our findings suggest that routine measurement of hsCRP in patients undergoing percutaneous coronary intervention in contemporary practice is unlikely to be beneficial.

Background— Spontaneous coronary artery dissection (SCAD) is an acute coronary event of uncertain origin. Clinical features and prognosis remain insufficiently characterized. Methods and Results— A retrospective single-center cohort study identified 87 patients with angiographically confirmed SCAD. Incidence, clinical characteristics, treatment modalities, in-hospital outcomes, and long-term risk of SCAD recurrence or major adverse cardiac events were evaluated. Mean age was 42.6 years; 82% were female. Extreme exertion at SCAD onset was more frequent in men (7 of 16 versus 2 of 71; P <0.001), and postpartum status was observed in 13 of 71 women (18%). Presentation was ST-elevation myocardial infarction in 49%. Multivessel SCAD was found in 23%. Initial conservative management (31 of 87) and coronary artery bypass grafting (7 of 87) were associated with an uncomplicated in-hospital course, whereas percutaneous coronary intervention was complicated by technical failure in 15 of 43 patients (35%) and 1 death. During a median follow-up of 47 months (interquartile range, 18–106 months), SCAD recurred in 15 patients, all female. Estimated 10-year rate of major adverse cardiac events (death, heart failure, myocardial infarction, and SCAD recurrence) was 47%. Fibromuscular dysplasia of the iliac artery was identified incidentally in 8 of 16 femoral angiograms (50%) undertaken before closure device placement and in the carotid arteries of 2 others with carotid dissection. Conclusions— SCAD affects a young, predominantly female population, frequently presenting as ST-elevation myocardial infarction. Although in-hospital mortality is low regardless of initial treatment, percutaneous coronary intervention is associated with high rates of complication. Risks of SCAD recurrence and major adverse cardiac events in the long term emphasize the need for close follow-up. Fibromuscular dysplasia is a novel association and potentially causative factor.

Abstract—Hypercholesterolemia (HC) is often associated with impaired peripheral and coronary vascular responses to endothelium-dependent vasodilators, which are probably due to low bioavailability of nitric oxide. To examine the effect of HC on renal vascular and tubular function, 22 domestic pigs were studied after being fed a 12-week normal (n=11) or HC (n=11) diet. Renal regional perfusion and intratubular contrast media concentration in each nephron segment (representing fluid reabsorption) were quantified in vivo with electron-beam computed tomography before and after a suprarenal infusion of either acetylcholine (6 pigs of each diet) or sodium nitroprusside (SNP; 5 pigs of each diet). An increase in cortical perfusion, observed in normal pigs with acetylcholine (+35±6%,P=0.002) and SNP (+12±4%,P=0.005), was blunted in the HC group (+8.8±4.0,P=0.01, and −4.6±4.0%,P=0.1, respectively,P=0.003 andP=0.005 compared with normal) as was an increase in medullary perfusion (+58±21 in normal versus +24±11% in HC,P=0.04). A decrease in the intratubular contrast media concentration in the distal tubule and collecting duct of normal pigs was observed in all tubular segments (and was significantly enhanced in the proximal tubule and Henle’s loop) in the HC group, which was associated with increased sodium excretion. The tubular and renal excretory responses to SNP were similar between the groups. In conclusion, early experimental HC in the pig attenuates renal perfusion response to both endothelium-dependent and -independent vasodilators possibly because of decreased bioavailability or decreased vascular responsiveness to nitric oxide. This vascular impairment may play a role in maladjusted renovascular responses and contribute to renal damage in later stages of atherosclerosis.