Citations

Abstract —Endothelin (ET) may mediate the enhanced coronary vasoconstriction associated with hypercholesterolemia. We hypothesized that short-term inhibition of ET receptors attenuates the coronary epicardial vasoconstrictor response to acetylcholine in experimental hypercholesterolemia. ET-1 (group I, n=5; 5 ng · kg −1 · min −1 ) and acetylcholine (group III, n=7; 10 −6 to 10 −4 mol/L) were given by intracoronary infusion in pigs. ET-1 and acetylcholine were also infused with the specific ETA-receptor blocker FR-139317 (5 μg · kg −1 · min −1 ; group II, n=6; group IV, n=6). Acetylcholine was also infused with the combined ET-receptor blocker, bosentan (0.5 mg/kg plus 1 mg · kg −1 · h −1 , group V, n=5). The ETB-receptor agonist sarafotoxin 6c (5 ng · kg −1 · min −1 ; n=4) was also infused. The percentage change in coronary artery diameter (%ΔCAD) to the infusions was measured at baseline and after 10 weeks of high-cholesterol diet in all animals. Sarafotoxin 6c mildly reduced %ΔCAD at baseline and 10 weeks (−10±2% and −12±3%, respectively). FR-139317 did not attenuate the epicardial vasoconstrictor response to ET-1 at baseline (%ΔCAD −18±8% for group I versus −12±6% for group II; P =NS) but did at 10 weeks (%ΔCAD −77±14% for group I versus −14±6% for group II; P <.05). FR-139317 did not affect the response to acetylcholine at baseline (%ΔCAD 5±2% for group III versus 7±3% for group IV, P =NS) or at 10 weeks (%ΔCAD −23±12% for group III versus −19±7% for group IV; P =NS). Bosentan did not affect the response to acetylcholine at baseline or 10 weeks. Short-term ET-receptor inhibition in experimental hypercholesterolemia attenuated the enhanced coronary epicardial vasoconstrictor effects of ET-1 but not acetylcholine-induced coronary epicardial vasoconstriction, suggesting that acetylcholine-induced coronary epicardial vasoconstriction may not be mediated by ET receptors.

Abstract The coronary vasoconstrictor effects of endothelins, mediated by both endothelin ETA and ETB receptors, may be differentially altered in pathophysiological states associated with endothelial dysfunction and elevated endothelin levels. Experimental hypercholesterolemia is associated with coronary endothelial dysfunction and increased circulating endothelin concentrations. These studies were designed to test the hypothesis that experimental hypercholesterolemia is characterized by a differentially altered coronary contractile response to ETA- and ETB-receptor stimulation, in vitro. Pigs were fed either a normal or a high-cholesterol diet for 10 to 13 weeks. Changes in the intraluminal diameter of pressurized small coronary arteries (<481±25 μm in diameter) to cumulative concentrations (10 −10 to 10 −6 mol/L) of endothelin-1 (ET-1), and sarafotoxin 6c (S6c), a specific ETB-receptor agonist, were measured using a video dimension analyzer. The maximal contraction attained with ET-1 was greater than with S6c in both normal (86±7% versus 47±7%, P =.001) and hypercholesterolemic (77±6% versus 37±7%, P <.001) pigs. At 10 −10 mol/L, vessels from hypercholesterolemic pigs manifested greater contraction to both ET-1 (23±6% versus 8±3%, P =.02) and S6c (17±5% versus 4±2%, P =.02). Incubation of arteries from hypercholesterolemic pigs with BQ-788 (ETB-receptor antagonist), but not FR-139317 (ETA-receptor antagonist), altered the contractile response to ET-1 at 10 −10 mol/L. Removal of the endothelium abolished the difference in response to S6c between normal and hypercholesterolemic pigs. These studies demonstrate that experimental hypercholesterolemia is characterized by enhanced coronary vasoconstriction to endothelins in vitro, the mechanism of which is mediated mainly through the ETB receptor. Thus, the ETB receptor has a role in regulation of coronary artery tone in both the steady-state and pathophysiological states.

Abstract The aim of this study was to examine the role of HDL subparticles with apolipoprotein (apo) A-I alone (LpA-I) and with apoA-I and apoA-II (LpA-I/A-II) in predicting coronary artery disease. Concentrations of these HDL subparticles were compared in 184 subjects with angiographically confirmed significant coronary artery disease (>50% stenosis of at least one vessel) and 191 age- and sex-matched control subjects without clinical coronary artery disease. LpA-I and LpA-I/A-II were measured with magnetic beads coated with anti–apoA-II antibodies to separate particles containing apoA-II from plasma. Total plasma cholesterol and triglyceride levels were similar in both groups. Although subjects with coronary artery disease had lower HDL cholesterol, plasma apoA-I, LpA-I, and LpA-I/A-II than age- and sex-matched control subjects without coronary artery disease, plasma apoA-I was the best predictor of coronary artery disease. In conclusion, LpA-I and LpA-I/A-II are lower in subjects with coronary artery disease but do not add to plasma apoA-I in predicting the presence of coronary artery disease.

Background— Prior studies demonstrate a direct relationship between treatment delays to primary percutaneous intervention and mortality in patients with ST-segment elevation myocardial infarction (STEMI). This analysis compared the relationship of symptom onset-to-balloon time and door-to-balloon time on mortality in patients with STEMI. Methods and Results— We analyzed different treatment delays (symptom onset-to-balloon time, door-to-balloon time) and mortality in 5745 STEMI patients. Baseline characteristics, flow grade, 90-day mortality, and clinical outcomes were compared in patients stratified by treatment delay. Multivariable logistic regression modeling was performed to assess the independent and relative effect of each treatment delay on 90-day mortality. Female sex, increased age, and worse thrombolysis in myocardial infarction flow grade were significantly associated with longer symptom onset-to-balloon times and door-to-balloon times. Longer symptom onset-to-balloon time was significantly associated with worse 90-day mortality (3.7%, 4.2%, and 6.5% for time delays <3 hours, 3 to 5 hours, and >5 hours, respectively, P <0.0001). Similarly, longer door-to-balloon times were significantly associated with worse 90-day mortality (3.2%, 4.0%, 4.6%, and 5.3% for delays <60 minutes, 60 to 90 minutes, 90 to 120 minutes, and ≥120 minutes respectively, P <0.0001). In a multivariate model of 90-day mortality, door-to-balloon time (χ 2 6.0, P <0.014), and symptom onset-to-hospital arrival (χ 2 9.8, P <0.007) remained independent determinants. Conclusions— Both symptom onset-to-balloon time and hospital door-to-balloon time are strongly associated with 90-day mortality following STEMI. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00091637.

Background— The Watchman Left Atrial Appendage System for Embolic Protection in Patients With AF (PROTECT AF) randomized trial compared left atrial appendage closure against warfarin in atrial fibrillation (AF) patients with CHADS 2 ≥1. Although the study met the primary efficacy end point of being noninferior to warfarin therapy for the prevention of stroke/systemic embolism/cardiovascular death, there was a significantly higher risk of complications, predominantly pericardial effusion and procedural stroke related to air embolism. Here, we report the influence of experience on the safety of percutaneous left atrial appendage closure. Methods and Results— The study cohort for this analysis included patients in the PROTECT AF trial who underwent attempted device left atrial appendage closure (n=542 patients) and those from a subsequent nonrandomized registry of patients undergoing Watchman implantation (Continued Access Protocol [CAP] Registry; n=460 patients). The safety end point included bleeding- and procedure-related events (pericardial effusion, stroke, device embolization). There was a significant decline in the rate of procedure- or device-related safety events within 7 days of the procedure across the 2 studies, with 7.7% and 3.7% of patients, respectively, experiencing events ( P =0.007), and between the first and second halves of PROTECT AF and CAP, with 10.0%, 5.5%, and 3.7% of patients, respectively, experiencing events ( P =0.006). The rate of serious pericardial effusion within 7 days of implantation, which had made up >50% of the safety events in PROTECT AF, was lower in the CAP Registry (5.0% versus 2.2%, respectively; P =0.019). There was a similar experience-related improvement in procedure-related stroke (0.9% versus 0%, respectively; P =0.039). Finally, the functional impact of these safety events, as defined by significant disability or death, was statistically superior in the Watchman group compared with the warfarin group in PROTECT AF. This remained true whether significance was defined as a change in the modified Rankin score of ≥1, ≥2, or ≥3 (1.8 versus 4.3 events per 100 patient-years; relative risk, 0.43; 95% confidence interval, 0.24 to 0.82; 1.5 versus 3.7 events per 100 patient-years; relative risk, 0.41; 95% confidence interval, 0.22 to 0.82; and 1.4 versus 3.3 events per 100 patient-years; relative risk, 0.43; 95% confidence interval, 0.22 to 0.88, respectively). Conclusion— As with all interventional procedures, there is a significant improvement in the safety of Watchman left atrial appendage closure with increased operator experience. Clinical Trial Registration— URL: http://clinicaltrials.gov . Unique identifier: NCT00129545.

Background— Existing models for outcome after percutaneous coronary interventions (PCIs) lack assessment of long-term prognosis. Our goal was to derive 1- and 5-year mortality and mortality/myocardial infarction (MI) risk models for PCI outcomes from simple, easily obtainable clinical and laboratory variables. Methods and Results— Using the Mayo Clinic registry, we analyzed long-term mortality and mortality/MI following PCIs on 9165 unique patients from January 1, 2001, through December 31, 2007. Cox proportional hazards regression was used to model the calculated risk score and major procedural complications. A total of 1243 patients died, and 696 had MI. Separate risk models derived from clinical, procedural, and laboratory characteristics were made for mortality and mortality/MI. Older age, comorbid conditions, low ejection fraction, acute MI, history of smoking, heart failure, hyperlipidemia, 3-vessel disease, procedural failure, ventricular arrhythmia during PCI, and low medication score were predictors of long-term mortality and mortality/MI. Simple integer scores stratified patients into low, moderate, high, and very high risk for subsequent events. Models had adequate goodness of fit, and areas under the receiver operating characteristic curve were 0.786 and 0.728 for mortality and mortality/MI, respectively, indicating good overall discrimination. Bootstrap analysis indicated that the model was not overfit to the available data set. Conclusions— Easily obtainable variables can be combined into a convenient risk scoring system at the time of patient dismissal following PCI to accurately predict long-term mortality and mortality/MI. This model may be useful for providing patients with individualized, evidence-based estimates of long-term risk.

Background— Circadian rhythms with regard to time of symptom onset for patients with acute myocardial infarction have been observed, although their relationship to outcomes has been debated. We evaluated these rhythms in patients with ST-elevation myocardial infarction as a function of the 24-hour circadian cycle. Methods and Results— The relationship between onset of symptoms during the 24-hour circadian cycle and prehospital delays from symptom onset to hospital arrival, timeliness of reperfusion, and in-hospital death was assessed in 2143 patients with ST-elevation myocardial infarction presenting from 2004–2008 at 1 of 3 tertiary-care healthcare ST-elevation myocardial infarction systems. There was a significant association between time of onset and the circadian cycle, with the greatest percentage (39%) of patients experiencing onset between 8 am and 3 pm ( P <0.001). Time of onset was associated with prehospital delay and timeliness of reperfusion. Patients with onset from 12 am to 5:59 am had median prehospital delays of 121 minutes versus 70 minutes from 12 pm to 5:59 pm ( P <0.001). Patients with onset time from 12 am to 5:59 am had median door-to-balloon times of 75 minutes versus 60 minutes from 6 am to 11:59 am ( P <0.001). Using multivariable modeling to control for baseline patient characteristics, prehospital delay, and timeliness of reperfusion, there was no significant association between time of symptom onset with in-hospital death. Conclusions— Patients with ST-elevation myocardial infarction exhibit significant circadian patterns in symptom onset, prehospital delay, and timeliness of reperfusion. Patients who develop symptoms from 12 am to 5:59 am present with longer prehospital delays and have longer door-to-balloon times. After multivariable adjustment, there was no significant association between circadian patterns of time of onset and in-hospital death.

Background— The prospective, multinational, randomized Synergy Between Percutaneous Coronary Intervention With TAXUS and Cardiac Surgery (SYNTAX) trial was designed to assess the optimal revascularization strategy between percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG), for patients with left main (LM) and/or 3-vessel coronary disease. Methods and Results— This observational hypothesis-generating analysis reports the results of a prespecified powered subgroup of 705 randomized patients who had LM disease among the 1800 patients with de novo 3-vessel disease and/or LM disease randomized to PCI with paclitaxel-eluting stents or CABG in the SYNTAX trial. Major adverse cardiac and cerebrovascular event rates at 1 year in LM patients were similar for CABG and PCI (13.7% versus 15.8%; Δ2.1% [95% confidence interval −3.2% to 7.4%]; P =0.44). At 1 year, stroke was significantly higher in the CABG arm (2.7% versus 0.3%; Δ−2.4% [95% confidence interval −4.2% to −0.1%]; P =0.009]), whereas repeat revascularization was significantly higher in the PCI arm (6.5% versus 11.8%; Δ5.3% [95% confidence interval 1.0% to 9.6%]; P =0.02); there was no observed difference between groups for other end points. When patients were scored for anatomic complexity, those with higher baseline SYNTAX scores had significantly worse outcomes with PCI than did patients with low or intermediate SYNTAX scores; outcomes for patients with CABG did not correlate with baseline SYNTAX score, but baseline EuroSCORE significantly predicted outcomes for both treatments. Conclusions— Patients with LM disease who had revascularization with PCI had safety and efficacy outcomes comparable to CABG at 1 year; longer follow-up is required to determine whether these 2 revascularization strategies offer comparable medium-term outcomes in this group of complex patients. Clinical Trial Registration— http://www.clinicaltrials.gov. Unique identifier: NCT00114972.

Background The American College of Cardiology released a scientific advisory that included a recommendation to delay elective of noncardiac surgery (NCS) for 1 yr after percutaneous coronary intervention (PCI) with a drug-eluting stent (DES). Methods This single-center, retrospective study examined the risk for complications of NCS performed within 2 yr after DES placement and examined whether this risk changed based on the time between procedures. The primary endpoint was major adverse cardiac events (MACEs) during the hospitalization for NCS. Bleeding events were analyzed as a secondary endpoint. Results From April 22, 2003, to December 31, 2006, a total of 520 patients underwent NCS within 2 yr after PCI with a DES at Mayo Clinic. The majority, 84%, of the DES placed were Cypher stents. The frequency of MACE was not found to be significantly associated with the time between PCI and NCS (rate of MACEs 6.4, 5.7, 5.9, and 3.3% at 0-90, 91-180, 181-365, and 366-730 days after PCI with DES, respectively; P = 0.727 for comparison across groups). Characteristics found to be associated with MACEs in univariate analysis were advanced age (P = 0.031), emergent NCS (P = 0.006), shock at time of PCI (P = 0.035), previous history of myocardial infarction (P = 0.046), and continuation of a thienopyridine (ticlopidine or clopidogrel) into the preoperative period (P = 0.040). The rate of transfusion did not seem to be associated with antiplatelet therapy use. Conclusions The risk of MACEs with NCS after DES placement was not significantly associated with time from stenting to surgery, but observed rates of MACEs were lowest after 1 yr.