Krishnankutty Sudhir

Everolimus-eluting versus paclitaxel-eluting stents in coronary artery disease.

BACKGROUND Previous studies have established the superiority of coronary everolimus-eluting stents over paclitaxel-eluting stents with respect to angiographic findings. However, these trials were not powered for superiority in clinical end points. METHODS We randomly assigned 3687 patients at 66 U.S. sites to receive everolimus-eluting stents or paclitaxel-eluting stents without routine follow-up angiography. The primary end point was the 1-year composite rate of target-lesion failure (defined as cardiac death, target-vessel myocardial infarction, or ischemia-driven target-lesion revascularization). RESULTS Everolimus-eluting stents were superior to paclitaxel-eluting stents with respect to the primary end point of target-lesion failure (4.2% vs. 6.8%; relative risk, 0.62; 95% confidence interval, 0.46 to 0.82; P=0.001). Everolimus-eluting stents were also superior with respect to the major secondary end point of the 1-year rate of ischemia-driven target-lesion revascularization (P=0.001) and were noninferior with respect to the major secondary end point of the 1-year composite rate of cardiac death or target-vessel myocardial infarction (P<0.001 for noninferiority; P=0.09 for superiority). The 1-year rates of myocardial infarction and stent thrombosis were also lower with everolimus-eluting stents than with paclitaxel-eluting stents (1.9% vs. 3.1%, P=0.02 for myocardial infarction; 0.17% vs. 0.85%, P=0.004 for stent thrombosis). Target-lesion failure was consistently reduced with everolimus-eluting stents as compared with paclitaxel-eluting stents in 12 prespecified subgroups, except in the subgroup of patients with diabetes (6.4% vs. 6.9%, P=0.80). CONCLUSIONS Everolimus-eluting stents, as compared with paclitaxel-eluting stents, resulted in reduced rates of target-lesion failure at 1 year, results that were consistent in all patients except those with diabetes, in whom the results were nonsignificantly different. (ClinicalTrials.gov number, NCT00307047.)

Testosterone Induces Dilation of Canine Coronary Conductance and Resistance Arteries In Vivo

BACKGROUND Although estrogens have been shown to be vasoactive hormones, the vascular effects of testosterone are not well defined. Like estrogen, testosterone causes relaxation of isolated rabbit coronary arterial segments. We examined the vasodilator effects of testosterone in vivo in the coronary circulation and the potential mechanisms of its actions. METHODS AND RESULTS Using simultaneous intravascular two-dimensional and Doppler ultrasound, we examined the effect of intracoronary testosterone in coronary conductance and resistance arteries in 10 anesthetized dogs (5 male, 5 female). We also assessed the contribution of NO, prostaglandins, ATP-sensitive K+ channels, and classic estrogen receptors to testosterone-induced vasodilation. Testosterone induced a significant increase in cross-sectional area, average coronary peak flow velocity, and calculated volumetric coronary blood flow at the 0.1 and 1 mumol/L concentrations. This effect was independent of sex. Pretreatment with N omega-nitro-L-arginine methyl ester to block NO synthesis decreased testosterone-induced increase in cross-sectional area, average coronary peak flow velocity, and coronary blood flow. Pretreatment with glybenclamide to assess the role of ATP-sensitive K+ channels did not influence testosterone-induced dilation in epicardial arteries but did attenuate its effect in the microcirculation. Pretreatment with indomethacin or the classic estrogen-receptor antagonist ICI 182,780 did not alter testosterone-induced changes. CONCLUSIONS Short-term administration of testosterone induces a sex-independent vasodilation in coronary conductance and resistance arteries in vivo. Acute testosterone-induced coronary vasodilation of epicardial and resistance vessels is mediated in part by endothelium-derived NO. ATP-sensitive K+ channels appear to play a role in the vasodilatory effect of testosterone in resistance arteries.

Mechanical strain of rat vascular smooth muscle cells is sensed by specific extracellular matrix/integrin interactions.

Cyclic mechanical strain (1 Hz) causes a mitogenic response in neonatal rat vascular smooth muscle cells due to production and secretion of PDGF. In this study, the mechanism for sensing mechanical strain was investigated. Silicone elastomer strain plates were coated at varying densities with elastin, laminin, type I collagen, fibronectin, or vitronectin. Strain was applied by cyclic application of a vacuum under the dishes. Cells adhered, spread, and proliferated on each matrix protein, but the mitogenic response to strain was matrix dependent. Strain increased DNA synthesis in cells on collagen, fibronectin, or vitronectin, but not in cells on elastin or laminin. When strain was applied on matrices containing both laminin and vitronectin, the mitogenic response to strain depended upon the vitronectin content of the matrix. Fibronectin, in soluble form (0-50 micrograms/ml), and the integrin binding peptide GRGDTP (100 micrograms/ml) both blocked the mitogenic response to mechanical strain in cells grown on immobilized collagen. Neither soluble laminin nor the inactive peptide GRGESP blocked the response to strain. GRGDTP did not alter the mitogenic response to exogenous PDGF or alpha-thrombin but did prevent the secretion of PDGF in response to strain. Furthermore, GRGDTP, but not GRGESP, prevented strain-induced expression of a PDGF-A chain promoter 890 bp-chloramphenicol acetyltransferase construct that was transiently transfected into vascular smooth muscle cells. Finally, the response to strain was abrogated by antibodies to both beta 3 and alpha v beta 5 integrins but not by an antibody to beta 1 integrins. Thus interaction between integrins and specific matrix proteins is responsible for sensing mechanical strain in vascular smooth muscle cells.

Randomized Comparison of Everolimus-Eluting and Paclitaxel-Eluting Stents : Two-Year Clinical Follow-Up From the Clinical Evaluation of the Xience V Everolimus Eluting Coronary Stent System in the Treatment of Patients With De Novo Native Coronary Artery Lesions (SPIRIT) III Trial

Background— In the prospective randomized Clinical Evaluation of the Xience V Everolimus Eluting Coronary Stent System in the Treatment of Patients with de novo Native Coronary Artery Lesions (SPIRIT) III trial, an everolimus-eluting stent (EES) compared with a widely used paclitaxel-eluting stent (PES) resulted in a statistically significant reduction in angiographic in-segment late loss at 8 months and noninferior rates of target vessel failure (cardiac death, myocardial infarction, or target vessel revascularization) at 1 year. The safety and efficacy of EES after 1 year have not been reported. Methods and Results— A total of 1002 patients with up to 2 de novo native coronary artery lesions (reference vessel diameter, 2.5 to 3.75 mm; lesion length ≤28 mm) were randomized 2:1 to EES versus PES. Antiplatelet therapy consisted of aspirin indefinitely and a thienopyridine for ≥6 months. Between 1 and 2 years, patients treated with EES compared with PES tended to have fewer episodes of protocol-defined stent thrombosis (0.2% versus 1.0%; P=0.10) and myocardial infarctions (0.5% versus 1.7%; P=0.12), with similar rates of cardiac death (0.3% versus 0.3%; P=1.0) and target vessel revascularization (2.9% versus 3.0%; P=1.0). As a result, at the completion of the 2-year follow-up, treatment with EES compared with PES resulted in a significant 32% reduction in target vessel failure (10.7% versus 15.4%; hazard ratio, 0.68; 95% confidence interval, 0.48 to 0.98; P=0.04) and a 45% reduction in major adverse cardiac events (cardiac death, myocardial infarction, or target lesion revascularization; 7.3% versus 12.8%; hazard ratio, 0.55; 95% confidence interval, 0.36 to 0.83; P=0.004). Among the 360 patients who discontinued clopidogrel or ticlopidine after 6 months, stent thrombosis subsequently developed in 0.4% of EES patients versus 2.6% of PES patients (P=0.10). Conclusions— Patients treated with EES rather than PES experienced significantly improved event-free survival at a 2-year follow-up in the SPIRIT III trial, with continued divergence of the hazard curves for target vessel failure and major adverse cardiac events between 1 and 2 years evident. The encouraging trends toward fewer stent thrombosis episodes after 6 months in EES-treated patients who discontinued a thienopyridine and after 1 year in all patients treated with EES rather than PES deserve further study.

Hormonal Therapy Increases Arterial Compliance in Postmenopausal Women

OBJECTIVES This study investigated the effects of hormonal therapy on large arterial properties. BACKGROUND Arterial stiffness is an emerging risk marker for coronary heart disease and is potentially modifiable. Postmenopausal use of hormonal therapy is associated with a lower risk of coronary heart disease. METHODS Total systemic arterial compliance (SAC) and pulse wave velocity (PWV) were determined in 26 premenopausal and 52 postmenopausal women, 26 of whom were taking hormonal therapy. RESULTS Arterial compliance was greater in the premenopausal group (mean +/- SEM 0.57 +/- 0.04 arbitrary compliance units [ACU]) than in the postmenopausal group not taking hormonal therapy (0.26 +/- 0.02 ACU, p = 0.001). Postmenopausal women taking hormonal therapy had a significantly increased total SAC compared with women not taking hormonal therapy (0.43 +/- 0.02 vs. 0.26 +/- 0.02 ACU, p = 0.001). PWV in the aortofemoral region in the premenopausal women was 6.0 +/- 0.2 vs. 8.9 +/- 0.3 m/s (p < 0.001) in untreated postmenopausal women. However, postmenopausal women taking hormonal therapy had a significantly lower PWV than those not taking hormonal therapy (7.9 +/- 0.2 vs. 8.9 +/- 0.3 m/s, p = 0.01). Eleven postmenopausal women had their hormone replacement therapy withdrawn for 4 weeks, resulting in a significant decrease in SAC and a significant increase in aortofemoral PWV. CONCLUSIONS The increased SAC and decreased PWV in women receiving hormonal therapy suggest that such therapy may decrease stiffness of the aorta and large arteries in postmenopausal women, with potential benefit for age-related cardiovascular disorders. The reduction of arterial compliance with age appears to be altered with hormonal therapy.

Evaluation of the Second Generation of a Bioresorbable Everolimus-Eluting Vascular Scaffold for the Treatment of De Novo Coronary Artery Stenosis

OBJECTIVES The aim of this study was to demonstrate that the prevention of early scaffold area shrinkage of the ABSORB BVS (Rev.1.1, Abbott Vascular, Santa Clara, California) was sustained and not simply delayed by a few months. BACKGROUND With improved scaffold design and modified manufacturing process of its polymer, the second iteration of ABSORB (BVS 1.1) has improved performance to prevent a scaffold area reduction at 6 months. METHODS Fifty-six patients were enrolled and received 57 ABSORB scaffolds. Quantitative coronary angiography, intravascular ultrasound (IVUS), analysis of radiofrequency backscattering, echogenicity and optical coherence tomography (OCT) were performed at baseline and at 12-month follow-up. RESULTS Overall the scaffold area remained unchanged with IVUS as well as with OCT, whereas the radiofrequency backscattering and the echogenicity of the struts decreased by 16.8% (p < 0.001) and 20% (p < 0.001), respectively; more specifically, the strut core area on OCT decreased by 11.4% (p = 0.003). Despite the absence of scaffold area loss, pharmacological vasomotion was restored. On an intention-to-treat basis, the angiographic late lumen loss amounted to 0.27 ± 0.32 mm with an IVUS relative decrease in minimal lumen area of 1.94% (p = 0.12), without significant changes in mean lumen area. The OCT at follow-up showed that 96.69% of the struts were covered and that malapposition, initially observed in 18 scaffolds was only detected at follow-up in 4 scaffolds. Two patients experienced peri-procedural and iatrogenic myocardial infarction, respectively, whereas 2 underwent repeat intervention, resulting in the major adverse cardiac event rate of 7.1% (4 of 56). CONCLUSIONS The 12-month performance of the second-generation ABSORB bioresorbable everolimus-eluting scaffold justifies the conduct of a randomized trial against current best standards. (A Clinical Evaluation of the Bioabsorbable Everolimus Eluting Coronary Stent System [BVS EECSS] in the Treatment of Patients With de Novo Native Coronary Artery Lesions; NCT00856856).

Premature Coronary Artery Disease Associated With a Disruptive Mutation in the Estrogen Receptor Gene in a Man

BACKGROUND While estrogens protect against coronary artery disease in women, it is unclear whether they influence cardiovascular function in men. The present report describes coronary vascular abnormalities and the lipoprotein profile of a male patient with estrogen insensitivity caused by a disruptive mutation in the estrogen-receptor gene. METHODS AND RESULTS Stress thallium scintigraphy, echocardiography, and electron-beam computed tomography (CT) scanning of the coronary arteries and detailed lipoprotein analysis were performed. Electron-beam CT scanning of the coronary arteries showed calcium in the left anterior descending artery. Lipoprotein analysis showed relatively low levels of total (130 mg/dL), LDL (97 mg/dL), and HDL (34 mg/dL) cholesterol; apolipoprotein A-I (91.7 mg/dL); and lipoprotein(a) (4.1 nmol/L), but normal levels of triglycerides (97 mg/dL) and pre-beta-1-HDL cholesterol (61 microg/mL). CONCLUSIONS The absence of functional estrogen receptors may be a novel risk factor for coronary artery disease in men.

Randomized Comparison of Everolimus- and Paclitaxel-Eluting Stents: 2-Year Follow-Up From the SPIRIT (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System) IV Trial

OBJECTIVES We sought to determine whether the differences in outcomes present between everolimus-eluting stents (EES) and paclitaxel-eluting stents (PES) in the SPIRIT (Clinical Evaluation of the XIENCE V Everolimus Eluting Coronary Stent System) IV trial at 1 year were sustained with longer-term follow-up. BACKGROUND In the SPIRIT IV trial, patients undergoing percutaneous coronary intervention who were randomized to EES compared with PES experienced lower 1-year rates of target lesion failure (cardiac death, target vessel myocardial infarction [MI], or ischemia-driven target lesion revascularization [TLR]), with significant reductions in the individual rates of MI, TLR, and stent thrombosis. METHODS We prospectively randomized 3,687 patients with up to 3 noncomplex previously untreated native coronary artery lesions to EES versus PES at 66 U.S. sites. Follow-up through 2 years is complete in 3,578 patents (97.0%). RESULTS Treatment with EES compared with PES reduced the 2-year rates of TLF (6.9% vs. 9.9%, p = 0.003), all MI (2.5% vs. 3.9%, p = 0.02), Q-wave MI (0.1% vs. 0.8%, p = 0.002), stent thrombosis (0.4% vs. 1.2%, p = 0.008), and ischemia-driven TLR (4.5% vs. 6.9%, p = 0.004), with nonsignificantly different rates of all-cause and cardiac mortality. Between 1 year and 2 years, there were no significant differences in adverse event rates between the 2 stent types. CONCLUSIONS In the large-scale, prospective, multicenter, randomized SPIRIT IV trial, the benefits of EES compared with those of PES present at 1 year were sustained at 2 years.

Estrogen Enhances Basal Nitric Oxide Release in the Forearm Vasculature in Perimenopausal Women

The mechanisms of estrogen-induced cardiovascular protection are incompletely understood. Acute estrogen administration enhances acetylcholine-induced vasorelaxation, suggesting that endothelium-dependent factors may be important. The effect of long-term estrogen supplementation on endothelial function has not been well defined. In this double-blind, randomized study, we examined endothelial function in forearm resistance arteries in 11 perimenopausal women before and after 8 weeks of estrogen supplementation (estradiol valerate, 2 mg daily, n = 6) or placebo (n = 5). Forearm blood flow was measured by venous-occlusion plethysmography, and vasoactive agents were infused through a brachial artery cannula in doses that did not influence blood pressure or heart rate. Estrogen supplementation significantly reduced systolic and diastolic pressures but had no effect on plasma lipoproteins. Estrogen did not alter the vasodilator responses to acetylcholine at doses of 9.25, 18.5, and 37 micrograms/min (rise in forearm blood flow before estrogen: 263 +/- 72%, 288 +/- 66%, and 383 +/- 84%, respectively; after estrogen: 205 +/- 34%, 260 +/- 44%, and 359 +/- 54%, P > .05.). Vasodilator responses to the endothelium-independent agent sodium nitroprusside (1.6 micrograms/min) were also unchanged after estrogen supplementation. However, estrogen enhanced vasoconstrictor responses to the nitric oxide synthase inhibitor NG-mono-methyl-L-arginine at doses of 1, 2, and 4 mumol/min (fall in fore-arm blood flow before estrogen: 13 +/- 9%, 20 +/- 7%, and 26 +/- 8%, respectively; after estrogen: 18 +/- 9%, 36 +/- 7%, and 47 +/- 7%, P = .04). Responses to vasoactive agents were unchanged after administration of placebo. Thus, in perimenopausal women, estrogen supplementation reduces blood pressure and enhances basal but not acetylcholine-induced nitric oxide release in fore-arm resistance arteries.

Endothelial dysfunction in a man with disruptive mutation in oestrogen-receptor gene

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