Spencer B. King

Integration of pre-hospital electrocardiograms and ST-elevation myocardial infarction receiving center (SRC) networks: impact on Door-to-Balloon times across 10 independent regions.

OBJECTIVESnThe aim of this study was to evaluate the rate of timely reperfusion for ST-elevation myocardial infarction (STEMI) with primary percutaneous coronary intervention (PPCI) in regional STEMI Receiving Center (SRC) networks.nnnBACKGROUNDnThe American College of Cardiology Door-to-Balloon (D2B) Alliance target is a >75% rate of D2B <or=90 min. Independent initiatives nationwide have organized regional SRC networks that coordinate universal access to 9-1-1 with the pre-hospital electrocardiogram (PH-ECG) diagnosis of STEMI and immediate transport to a SRC (designated PPCI-capable hospital).nnnMETHODSnA pooled analysis of 10 independent, prospective, observational registries involving 72 hospitals was performed. Data were collected on all consecutive patients with a PH-ECG diagnosis of STEMI. The D2B and emergency medical services (EMS)-to-balloon (E2B) times were recorded.nnnRESULTSnParamedics transported 2,712 patients with a PH-ECG diagnosis of STEMI directly to the nearest SRC. A PPCI was performed in 2,053 patients (76%) with an 86% rate of D2B <or=90 min (95% confidence interval: 84.4% to 87.4%). Secondary analyses of this cohort demonstrated a 50% rate of D2B <or=60 min (n = 1,031), 25% rate of D2B <or=45 min (n = 517), and an 8% rate of D2B <or=30 min (n = 155). A tertiary analysis restricted to 762 of 2,053 (37%) cases demonstrated a 68% rate of E2B <or=90 min.nnnCONCLUSIONSnTen independent regional SRC networks demonstrated a combined 86% rate of D2B <or=90 min, and each region individually surpassed the American College of Cardiology D2B Alliance benchmark. In areas with regional SRC networks, 9-1-1 provides entire communities with timely access to quality STEMI care.

Endothelium-Dependent Vasomotor Dysfunction in Pig Coronary Arteries With Paclitaxel-Eluting Stents Is Associated With Inflammation and Oxidative Stress

OBJECTIVESnWe sought to evaluate coronary epicardial and intramyocardial resistance, arterial vasomotor function, local inflammatory reaction, and superoxide anion (O(2)(.-)) production after overlapping paclitaxel-eluting stent (PES) implantation in a porcine model.nnnBACKGROUNDnPES implantation has been shown to elicit coronary vasomotor dysfunction. However, underlying mechanisms remain largely unknown.nnnMETHODSnNine pigs received overlapping PES and bare-metal stents (BMS) in the coronary arteries, and 3 sham animals were naïve. At 1 month, inflammatory response at the overlapped region was assessed by histopathology and scanning electron microscopy. Endothelial vasomotor function and O(2)(*-) at nonstented coronary reference segments were measured by angiography and organ chamber tensiometry, and lucigenin luminometry; vasomotor function of distal resistance arteries was measured by myography.nnnRESULTSnPaclitaxel-eluting stents showed reduced late lumen loss, but inflammation and luminal inflammatory cell adherence were higher than for BMS (p < 0.001) at overlapped segments. Endothelium-dependent relaxation to substance P was significantly impaired in PES at nonstented coronary reference segments (>or=15 mm proximally and distally) and perfusion bed resistance arteries (p < 0.05). In contrast, endothelium-independent relaxation to nitroglycerin and sodium-nitroprusside was similar between groups. Local O(2)(*-) production at both proximal and distal nonstented coronary reference segments was elevated for PES when compared with O(2)(*-) production in BMS and naïve arteries (p < 0.001).nnnCONCLUSIONSnAbnormal endothelium-dependent relaxation at both coronary conduit and resistance arteries was demonstrated after overlapping PES implantation. Profound localized inflammatory reaction, as well as enhanced local oxidative stress, may contribute to vasomotor dysfunction.

Nobori stent shows less vascular inflammation and early recovery of endothelial function compared with Cypher stent.

OBJECTIVESnThe current study sought to examine inflammation at the stented segments of Nobori (Terumo Corporation, Tokyo, Japan) and Cypher (Cordis, Miami, Florida) drug-eluting stents (DES), as well as free radical production and endothelial function of the adjacent nonstented segments in a pig coronary model.nnnBACKGROUNDnNobori is a novel DES, incorporating a biolimus A9-eluting biodegradable polymer coated only on the abluminal surface of the stent. These unique features may favorably affect inflammation and endothelial function, as compared to the currently marketed DES. Presently, pre-clinical data on direct comparison of the various generations of DES are not available.nnnMETHODSnA total of 18 DES were implanted in pig coronary arteries and subsequently explanted at 1 month. Stented segments were assessed by angiography and histology. Ex vivo vasomotor function and superoxide production in segments proximal and distal to the stent were determined. The vasoconstriction, endothelial-dependent relaxation, and endothelial-independent relaxation of proximal and distal nonstented segments were measured.nnnRESULTSnHistological evaluation revealed lower inflammatory response with Nobori than with Cypher DES. There is trend for lower angiographic percentage diameter stenosis in Nobori versus Cypher groups (p = 0.054). There was increased endothelium-dependent relaxation, decreased endothelin-1-mediated contraction, and less superoxide production in the vessel segments proximal and distal to Nobori versus Cypher stents.nnnCONCLUSIONSnOur data show significantly lower inflammatory response in the stented segments, and rapid recovery of endothelial function of peristent segments in the Nobori group compared with Cypher DES group at 1 month in porcine coronary artery model.

Impact of the Definition Utilized on the Rate of Contrast-Induced Nephropathy in Percutaneous Coronary Intervention

Several definitions have been used to assess rates of contrast-induced nephropathy (CIN) in patients undergoing percutaneous coronary intervention (PCI). Whether the definition influences observed rates of CIN is unclear. The Oxilan Registry was the first-ever prospective analysis of the efficacy and safety of ioxilan (low-osmolar and low-viscosity contrast medium), including rates of CIN assessed by multiple definitions, in PCI. From July 2006 to June 2007, consecutive patients undergoing PCI using ioxilan were enrolled. Serum creatinine (SCr) and estimated glomerular filtration rate (eGFR) were assessed at baseline and 3 to 5 days after PCI. CIN was defined as SCr increase >or=0.5 mg/dl, eGFR decrease >or=25%, SCr increase >or=25%, or the composite. Of 400 patients (age 62 +/- 11 years), 19% were women, 37% were diabetic, 22% were anemic, and 8% had a history of congestive heart failure. Baseline SCr was 1.12 +/- 0.3 mg/dl and 24% had an eGFR <60 ml/min. CIN rates were 3.3% (SCr increase >or=0.5 mg/dl), 7.6% (eGFR decrease >or=25%), 10.2% (SCr increase >or=25%), and 10.5% (composite). Hospitalization was prolonged in 3.4% of patients with CIN and none required dialysis. There were no deaths or severe allergic reactions. Non-ST-elevation myocardial infarction and repeat revascularization each occurred in 0.8%. In conclusion, in this unselected population undergoing PCI, CIN ranged in frequency from 3.3% to 10.5% depending on the definition used and was not associated with in-hospital mortality or substantial morbidity, such as dialysis. The wide variation in CIN and its lack of association with adverse outcomes underscore the need for a standardized, clinically relevant definition.

Combination of plaque burden, wall shear stress, and plaque phenotype has incremental value for prediction of coronary atherosclerotic plaque progression and vulnerability

AIMSnLarge plaque burden, certain phenotypes, and low wall shear stress (WSS) are associated with adverse outcomes and high WSS with development of plaque vulnerability. We aimed to investigate the incremental value of the combination of plaque burden, WSS and plaque phenotype for prediction of coronary atherosclerotic plaque progression and vulnerability.nnnMETHODSnTwenty patients with CAD underwent baseline and 6-month follow-up coronary virtual histology-intravascular ultrasound (VH-IVUS) and computational fluid dynamics modeling for calculation of WSS. Low WSS was defined as <10 dynes/cm(2) and high WSS as ≥25 dynes/cm(2). Baseline plaque characteristics and WSS were related to plaque progression and vulnerability.nnnRESULTSnIn 2249 VH-IVUS frames analyzed, coronary segments with both plaque burden >40% and low WSS had significantly greater change in plaque area at follow-up (+0.68 ± 1.05 mm(2)), compared to segments with plaque burden >40% without low WSS (-0.28 ± 1.32 mm(2)) or segments with low WSS and plaque burden ≤40% (+0.05 ± 0.71 mm(2)) (p = 0.047). Among plaque phenotypes, pathologic intimal thickening (PIT) had the greatest increase in necrotic core (NC) area (p = 0.06) and greatest decrease in fibro-fatty (FF) area (p < 0.0001). At follow-up, compared to segments with either plaque burden >60%, PIT, or high WSS, those with a combination of plaque burden >60%, PIT, and high WSS developed greater increase in NC area (p = 0.002), greater decrease in FF (p = 0.004) and fibrous areas (p < 0.0001), and higher frequency of expansive remodeling (p = 0.019).nnnCONCLUSIONnCombination of plaque burden, WSS, and plaque phenotype has incremental value for prediction of coronary plaque progression and increased plaque vulnerability in patients with non-obstructive CAD.

Ambulatory discharge after transradial coronary intervention: Preliminary US single-center experience (Same-day TransRadial Intervention and Discharge Evaluation, the STRIDE Study)

BACKGROUNDnAlthough the safety and cost-effectiveness of same-day discharge after uncomplicated transradial percutaneous coronary intervention (TR-PCI) is well established in Europe and Asia, such data are not available for US patients.nnnMETHODSnAll patients who underwent TR-PCI at our high-volume US medical center between 2004 and 2007 were included in this study. The primary end point was in-hospital adverse clinical outcomes between 6 and 24 hours postprocedure.nnnRESULTSnA total of 450 patients were included in this study (aged 59 +/- 11 years). Of these, 13% were female, 27% were diabetic, 6% had peripheral vascular disease, and 5% had chronic kidney disease. Procedural indications included stable angina (49%), unstable angina (31%), non-ST elevation myocardial infarction (NSTEMI) (17%), and ST elevation myocardial infarction (STEMI) (3%). All patients received an intra-arterial cocktail of heparin, verapamil, and nitroglycerin, and 13% of patients received glycoprotein IIb/IIIa inhibitors. Seven percent of patients had 3-vessel disease, 3% had bypass grafts stenoses, and 20% had class B(2)/C lesions. Procedural success rate was 96%. A total of 24 (5.3%) postprocedural complications were observed; however, none occurred between hours 6 to 24, the time differential between same-day and next-day discharge. Thirteen patients (2.9%) experienced significant complications within the first 6 hours (MI, urgent repeat revascularization, and ventricular tachycardia). Eleven (2.4%) spontaneously resolved minor access complications developed. There were 12 same-day discharges according to the operators discretion; none required readmission.nnnCONCLUSIONSnAlthough a low incidence of complications did occur, none would have been impacted by same-day discharge. Those observed before 6 hours would have prevented early discharge, and those occurring after 24 hours would have been unaffected by routine next-day discharge. This observational study demonstrated the safety and feasibility for a prospective evaluation of ambulatory TR-PCI in an American practice setting.

Vasomotor Function After Paclitaxel-Coated Balloon Post-Dilation in Porcine Coronary Stent Model

OBJECTIVESnThe purpose of this study was to evaluate endothelial function after post-dilation of bare-metal stents with paclitaxel-coated balloons (PCB) or non-drug-coated balloons (non-DCB) in a porcine model.nnnBACKGROUNDnDCB are an attractive alternative to drug-eluting stents because they provide short duration of drug exposure, while potentially inhibiting in-stent restenosis. Drug-eluting stents are associated with impaired endothelial function. It is unknown whether this abnormal vasomotor function is mitigated by reduced duration of drug exposure.nnnMETHODSnThirteen pigs underwent bare-metal stent implantation (arteries, n = 30), followed by post-dilation with either PCB (SeQuent Please, B. Braun Melsungen AG, Berlin, Germany) (n = 17) or non-DCB (n = 13). Five pigs with unstented arteries (n = 14) were controls. Coronary vasomotion was assessed 1 month after stent implantation, using acetylcholine (Ach) and nitroglycerin. Measurements were obtained for distal segments.nnnRESULTSnAngiographic late loss and histological area stenosis were similar between PCB and non-DCB. However, the percentage of diameter change in response to Ach was diminished with PCB (p < 0.05), when compared with either non-DCB or naive arteries. There was no difference between non-DCB and naive arteries. Inflammatory score and intramural fibrin grading were significantly greater in PCB than non-DCB (p < 0.05). Additionally, inflammatory cell infiltration in the stented segments correlated with the degree of percentage of diameter change in response to Ach, at distal regions.nnnCONCLUSIONSnPost-dilation of bare-metal stents with PCB was associated with impaired vasodilatory response to Ach distal to the treated segments. Vasodilatory response after post-dilation with non-DCB was similar to control arteries.

Clinical and Angiographic Features of Small Vessel Stenting in the Drug-Eluting Stent Era

This study was designed to investigate the clinical and angiographic features and procedural outcomes of small‐vessel stenting in a real‐world experience during the transition era between drug‐eluting stents (DES) and bare‐metal stents (BMS).

A comparison of drug eluting stent biocompatibility between third generation NOBORI biolimus A9-eluting stent and second generation XIENCE V everolimus-eluting stent in a porcine coronary artery model☆☆☆

BACKGROUND AND PURPOSEnNOBORI biolimus A9-eluting stent (BES) is the third generation drug eluting stent (DES) with only abluminal biodegradable polymer. Recent clinical trials have indicated that the BES is non-inferior to the XIENCE V everolimus-eluting stent (EES). Meanwhile, potential superiority of biodegradable polymer BES over current generation DES has not been addressed. The aim of this preclinical study was to assess and compare the biocompatibility of both BES and EES in porcine coronary arteries.nnnMETHODS AND MATERIALSnBES with length of 24-mm (n=9) and EES with length of 23-mm (n=9) were both implanted in porcine coronary arteries. At 28 days endothelium-dependent vasomotion was assessed by acetylcholine (Ach) and subsequently measurements of endothelial superoxide production, histological evaluations and microarray gene analyses were performed.nnnRESULTSnAngiographic and histological in-stent stenoses were significantly suppressed in BES compared with EES. Histopathological assessment showed lower inflammatory score as well as fibrin and injury scores in BES as compared with EES. On the contrary, paradoxical vasoconstriction to Ach was frequently observed in EES-treated vessels compared with BES-treated vessels. Additionally, gene expressions of inflammatory cytokines and chemokines were upregulated in vessels treated with EES compared with BES in microarray pathway specific analyses.nnnCONCLUSIONSnImplantation of BES revealed less inflammation and foreign-body immunoreaction than EES, suggesting more enhanced biocompatibility of BES compared with EES at 28 days in porcine coronary arteries.

Tirofiban in Coronary Intervention—The RESTORE Trial

Atheromatous plaque rupture, platelet activation with consequent thrombus formation and impairment of coronary arterial blood flow is a common theme in acute coronary syndromes (ACS) (1–4). The importance of antiplatelet therapy in the treatment of acute myocardial infarction (MI) was amply demonstrated in the second International Study of Infarct Survival (ISIS-2). At present, aspirin and to a lesser extent heparin, are used in nearly all patients with ACS. In spite of the improvements in prognosis that these treatments have brought, the incidence of adverse events in patients with ACS is still significant (5–8) and demonstrates the need for further improvement. There has been a rapid expansion of data from large multicenter trials on the use of IIb/IIIa receptor antagonists in the full spectrum of ACS. This is in part related to a recognition of the limitations of other antiplatelet agents, a better understanding of the mechanisms of platelet activation and aggregation. The realization that the GPIIb/IIIa platelet receptor is the final common pathway through which all the platelet agonists exhibit their effects on platelet aggregation make this receptor a promising target for antiplatelet therapy (9).