Ten-year clinical outcomes from a randomized trial comparing new-generation everolimus-eluting stent versus first-generation Sirolimus-eluting stent: Results from the RESET extended study.

BACKGROUND: New-generation drug-eluting stents (DES) achieved technological innovations and reported clinical advantages as compared with first-generation DES in clinical trials with 3-5 years follow-up. However, detailed clinical outcome data in very long-term follow-up is still scarce. OBJECTIVES: To evaluate 10-year clinical outcomes after first- and new-generation DES implantation. METHODS: In this extende follow-up study of the RESET, which is a largest randomized trial comparing everolimus-eluting stent (EES) with Sirolimus-eluting stent (SES), the study population consisted of 2892 patients from 84 centers. The primary efficacy and safety endpoints were target lesion revascularization (TLR) and a composite of death or myocardial infarction (MI), respectively. Complete 10-year follow-up was achieved in 87.9% of patients. RESULTS: Cumulative 10-year incidences of TLR and non-TLR were not significantly different between EES and SES (13.9% vs. 15.7%, Log-rank p = 0.20, and 33.4% vs. 31.3%, Log-rank p = 0.30). The cumulative 10-year incidence of death/MI was also not significantly different between the groups (32.5% vs. 34.4%, Log-rank p = 0.18). Cumulative 10-year incidence of definite stent thrombosis was numerically lower in EES than in SES (1.0% vs. 1.7%, Log-rank p = 0.16). The lower risk of EES relative to SES was significant for a composite endpoint of target lesion failure (TLF: 19.6% vs. 24.9%, Log-rank p = 0.001) and target vessel failure (TVF: 26.7% vs. 31.4%, Log-rank p = 0.006). CONCLUSION: During 10-year of follow-up, the risks for primary efficacy and safety endpoints were not significantly different between new-generation EES and first-generation SES, although EES compared with SES was associated with a lower risk for composite endpoints such as TLF and TVF.

7-Year Outcomes of a Randomized Trial Comparing the First-Generation Sirolimus-Eluting Stent Versus the New-Generation Everolimus-Eluting Stent: The RESET Trial.

OBJECTIVES: The aim of this study was to compare 7-year outcomes between the first-generation sirolimus-eluting stent (SES) and the new-generation everolimus-eluting stent (EES) in a randomized clinical trial. BACKGROUND: There is a scarcity of very long-term (beyond 5 years) data from clinical trials investigating whether new-generation drug-eluting stents have clear clinical advantages over first-generation drug-eluting stents. METHODS: RESET (Randomized Evaluation of Sirolimus-Eluting Versus Everolimus-Eluting Stent Trial) is the largest randomized trial comparing EES with SES (NCT01035450). Among a total of 3,197 patients in the original RESET population from 100 centers, the present extended 7-year follow-up study was conducted in 2,667 patients from 75 centers after excluding those patients enrolled from centers that denied participation. Complete 7-year follow-up was achieved in 91.5% of patients. RESULTS: The cumulative 7-year incidence of the primary efficacy endpoint of target lesion revascularization was not significantly different between EES and SES (10.2% vs. 11.7%; hazard ratio: 0.87; 95% confidence interval: 0.68 to 1.10; p = 0.24). The risk for the primary safety endpoint of death or myocardial infarction trended lower with EES than with SES (20.6% vs. 23.6%; hazard ratio: 0.85; 95% confidence interval: 0.72 to 1.005; p = 0.06). The cumulative 7-year incidence of definite stent thrombosis was very low and similar between EES and SES (0.9% vs. 1.0%; p = 0.82). The lower risk of EES relative to SES was significant for the composite secondary endpoint of target lesion failure (13.3% vs. 18.1%; hazard ratio: 0.72; 95% confidence interval: 0.59 to 0.88; p = 0.001). CONCLUSIONS: During 7 years of follow-up, the risk for target lesion revascularization was not significantly different between the new-generation EES and the first-generation SES.

Randomized comparison between 2-link cell design biolimus A9-eluting stent and 3-link cell design everolimus-eluting stent in patients with de novo true coronary bifurcation lesions: the BEGIN trial.

The appropriate stent platform for treating coronary bifurcation lesions (CBLs) remains controversial. Previous bench tests have demonstrated the superiority of a 2-link cell design to 3-link cell design for creating inter-strut dilation at the side branch ostium. This randomized multicenter prospective BEGIN trial compared the biodegradable polymer-based biolimus A9-eluting stent (2-link BES) with the durable polymer-based cobalt chromium everolimus-eluting stent (3-link EES) in 226 patients with de novo CBLs. Patients with true bifurcations, defined as > 50% stenosis in the main vessel and side branch (SB) and an SB diameter > 2.25 mm, were enrolled. Guide wire re-crossing to the distal cell (near the carina) in the jailed SB and final kissing inflation were recommended. The SB angiographic endpoint was < 50% stenosis diameter. Left-main CBLs (13.5% vs. 13.0%) and 2-stent technique (30.6% vs. 22.6%) rates were similar. The primary endpoints (minimum lumen diameter at the SB ostium measured at an independent core laboratory at the 8-month follow-up) were comparable (1.64 ± 0.50 mm vs. 1.63 ± 0.51 mm, p = 0.976). There was no significant difference in composite outcomes of cardiac death, myocardial infarction, or target vascular revascularization at 12 months (7.4% vs. 8.0%, p = 0.894). Two-link BES and 3-link EES showed similar 8-month angiographic and 1-year clinical outcomes for true CBLs.

Impact of Angiographic Residual Stenosis on Clinical Outcomes After New-Generation Drug-Eluting Stents Implantation: Insights From a Pooled Analysis of the RESET and NEXT Trials.

BACKGROUND: Previous intravascular ultrasound studies suggested the association of stent underexpansion with increased risk of stent thrombosis and restenosis. However, no previous study has addressed the association of the suboptimal angiographic result with target-lesion revascularization (TLR) in patients receiving new-generation drug-eluting stents (DES). METHODS AND RESULTS: RESET (Randomized evaluation of sirolimus-eluting versus everolimus-eluting stent trial) and NEXT (NOBORI biolimus-eluting versus XIENCE/PROMUS everolimus-eluting stent trial) are prospective, multicenter, randomized "DES versus DES" trials; 3196 patients and 3235 patients were enrolled in the RESET and NEXT, respectively. Using the pooled individual patient-level data, the current study population consisted of 3679 patients who received single-lesion treatment using new-generation DES such as everolimus-eluting stent and biolimus-eluting stent. The study population was divided into 3 groups according to the residual in-stent % diameter stenosis (%DS) after stent implantation by offline quantitative coronary angiography assessed in a core angiographic laboratory (optimal group: %DS <10%, intermediate group: %DS=10% to 20%, suboptimal group: %DS ≧20%). The cumulative 3-year incidence of TLR was significantly higher in the suboptimal group than in the intermediate and optimal groups (9.8% versus 5.8% versus 5.7%, log-rank P=0.004). Even after adjusting for the clinical, angiographic, and procedural characteristics, the excess TLR risk of the suboptimal group relative to the optimal group remained significant (hazard ratio: 1.65, 95% confidence interval, 1.14-2.41, P=0.009). The excess TLR risk of the suboptimal group relative to the optimal group was consistently seen across all the subgroups including heavy calcification. CONCLUSIONS: The residual angiographic in-stent %DS ≥20% was associated with increased risk for TLR in patients treated with the new-generation DES.

Second-Generation vs. First-Generation Drug-Eluting Stents in Patients With Calcified Coronary Lesions　- Pooled Analysis From the RESET and NEXT Trials.

BACKGROUND: The comparative efficacy of second-generation (G2) vs. first-generation (G1) drug-eluting stents (DES) for calcified coronary lesions is unknown.Methods and Results:We compared the 3-year clinical outcomes of patients with G1- or G2-DES according to the presence or absence of calcified coronary lesions as assessed in an angiographic core laboratory using data from 2 large-scale prospective multicenter randomized trials, RESET and NEXT. G1-DES and G2-DES were implanted in 299 and 1,033 patients, respectively, in the Calc stratum (≥1 lesion with moderate/severe calcification), and 1,208 and 3,550 patients, respectively, in the Non-calc stratum (no/mild calcification). The patients in the Calc stratum had a significantly higher adjusted risk for the primary outcome measure (any target-lesion revascularization (TLR)) than those in the Non-calc stratum (HR: 1.38, 95% CI: 1.11-1.71, P=0.004). The cumulative 3-year incidence of any TLR was not significantly different between the G1-DES and G2-DES groups in both the Calc and Non-calc strata (12.1% vs. 9.7%, P=0.22, and 6.8% vs. 6.1%, P=0.44, respectively). After adjusting for confounders, the effect of G2DES relative to G1-DES for any TLR remained insignificant in both the Calc and Non-calc strata (HR: 0.78, 95% CI: 0.48-1.25, P=0.3, and HR: 0.84, 95% CI: 0.61-1.17, P=0.31, respectively, P interaction=0.55). CONCLUSIONS: The effect of G2-DES relative to G1-DES for TLR was not significantly different regardless of the presence or absence of lesion calcification.

Final 3-Year Outcome of a Randomized Trial Comparing Second-Generation Drug-Eluting Stents Using Either Biodegradable Polymer or Durable Polymer: NOBORI Biolimus-Eluting Versus XIENCE/PROMUS Everolimus-Eluting Stent Trial.

BACKGROUND: There is a paucity of data reporting the clinical outcomes of biodegradable polymer biolimus-eluting stent (BP-BES) compared with durable polymer everolimus-eluting stent (DP-EES) beyond 1 year after stent implantation when the polymer is fully degraded. METHODS AND RESULTS: The NOBORI Biolimus-Eluting Versus XIENCE/PROMUS Everolimus-Eluting Stent Trial (NEXT) is a prospective, multicenter, randomized, open-label, noninferiority trial comparing BP-BES with DP-EES in patients scheduled for percutaneous coronary intervention using drug-eluting stent (DES) without any exclusion criteria among 98 participating centers in Japan. The trial was designed to evaluate noninferiority of BP-BES relative to DP-EES in terms of any target-lesion revascularization at 1 year and death or myocardial infarction at 3 years. Between May and October 2011, 3235 patients were randomly assigned to receive either BP-BES (1617 patients) or DP-EES (1618 patients). Complete 3-year follow-up was achieved in 97.6% of patients. At 3 years, the primary safety end point of death or myocardial infarction occurred in 159 patients (9.9%) in the BP-BES group and in 166 patients (10.3%) in the DP-EES group, demonstrating noninferiority of BP-BES relative to DP-EES (P noninferiority<0.0001 and P superiority=0.7). Cumulative incidence of target-lesion revascularization was not significantly different between the 2 groups (7.4% versus 7.1%; P=0.8). By a landmark analysis at 1 year, the cumulative incidences of death or myocardial infarction and target-lesion revascularization were also not significantly different between the 2 groups (4.6% versus 5.2%; P=0.46 and 3.3% versus 2.7%; P=0.39, respectively). CONCLUSIONS: Safety and efficacy outcomes of BP-BES were non inferior to those of DP-EES 3 years after stent implantation. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT01303640.

Development of new risk score for pre-test probability of obstructive coronary artery disease based on coronary CT angiography.

Existing methods to calculate pre-test probability of obstructive coronary artery disease (CAD) have been established using selected high-risk patients who were referred to conventional coronary angiography. The purpose of this study is to develop and validate our new method for pre-test probability of obstructive CAD using patients who underwent coronary CT angiography (CTA), which could be applicable to a wider range of patient population. Using consecutive 4137 patients with suspected CAD who underwent coronary CTA at our institution, a multivariate logistic regression model including clinical factors as covariates calculated the pre-test probability (K-score) of obstructive CAD determined by coronary CTA. The K-score was compared with the Duke clinical score using the area under the curve (AUC) for the receiver-operating characteristic curve. External validation was performed by an independent sample of 319 patients. The final model included eight significant predictors: age, gender, coronary risk factor (hypertension, diabetes mellitus, dyslipidemia, smoking), history of cerebral infarction, and chest symptom. The AUC of the K-score was significantly greater than that of the Duke clinical score for both derivation (0.736 vs. 0.699) and validation (0.714 vs. 0.688) data sets. Among patients who underwent coronary CTA, newly developed K-score had better pre-test prediction ability of obstructive CAD compared to Duke clinical score in Japanese population.

Long-term clinical outcomes after everolimus- and sirolimus-eluting coronary stent implantation: final 3-year follow-up of the Randomized Evaluation of Sirolimus-Eluting Versus Everolimus-Eluting Stent Trial.

BACKGROUND: Long-term clinical outcomes of everolimus-eluting stent (EES) compared with sirolimus-eluting stent (SES) have not been evaluated fully yet, especially whether EES implantation could positively affect late adverse events reported after SES implantation occurring >1 year. METHODS AND RESULTS: In this all-comer prospective multicenter randomized open-label trial, 3196 patients were assigned randomly to implant either EES (n=1596) or SES (n=1600). At 3 years, EES was noninferior to SES on the primary safety end point (all-cause death or myocardial infarction; 10.1% versus 11.5%; noninferiority P <0.001; and superiority P=0.19). Cumulative incidence of definite stent thrombosis was low and was not significantly different between the 2 groups (0.5% versus 0.6%; P=0.81). There was no significant difference in the efficacy end point of target-lesion revascularization between the EES and SES groups (6.6% versus 7.9%; P=0.16). However, the cumulative incidence of target-lesion failure (cardiac death/target-vessel myocardial infarction/ischemia-driven target-lesion revascularization) was significantly lower in the EES group than in the SES group (8.8% versus 11.4%; P=0.01). By a landmark analysis at 1 year, the cumulative incidence of very late stent thrombosis and late target-lesion revascularization was not significantly different between the 2 groups (0.2% versus 0.2%; P=0.99 and 2.2% versus 2.9%; P=0.21, respectively). CONCLUSIONS: The efficacy and safety outcomes for this trial after EES implantation remained comparable with those after SES implantation through 3-year follow-up. However, improvement of clinical outcome after EES implantation compared with SES implantation was suggested by the significantly lower cumulative incidences of target-lesion failure, which has been the most widely used primary end point in the stent-versus-stent trials. CLINICAL TRIAL REGISTRATION URL: http://www.clinicaltrials.gov. Unique identifier: NCT01035450.

A novel HCN4 mutation, G1097W, is associated with atrioventricular block.

BACKGROUND: Loss-of-function mutations in the HCN4 gene have been shown to be associated with sinus dysfunction, but there are no reports on HCN4-mediated atrioventricular (AV) block. A novel missense HCN4 mutation G1097W was identified in a 69 year-old Japanese male with AV block, and we characterized the functional consequences of If-like channels reconstituted with the heterozygous HCN4 mutation. METHODS AND RESULTS: Wild-type (WT) HCN4 or/and HCN4-G1097W were expressed in a heterologous cell expression system. A functional assay using a whole-cell patch-clamp demonstrated that the mutant If-like currents were activated at more negative voltages compared to WT currents, while they retained the sensitivity to changes in intracellular cyclic adenosine monophosphate (cAMP) levels. Co-expression of G1097W with WT channels showed dominant-negative effects, including a reduction in peak currents and a negative voltage shifting on reconstituted currents. CONCLUSIONS: The HCN4-G1097W mutant channels displayed a loss-of-function type modulation on cardiac If channels and thus could predispose them to AV nodal dysfunction. These data provide a novel insight into the genetic basis for the AV block.

Biodegradable polymer biolimus-eluting stent versus durable polymer everolimus-eluting stent: a randomized, controlled, noninferiority trial.

OBJECTIVES: NEXT (NOBORI Biolimus-Eluting Versus XIENCE/PROMUS Everolimus-Eluting Stent Trial) was designed for evaluating the noninferiority of a biolimus-eluting stent (BES) relative to an everolimus-eluting stent (EES) in terms of target lesion revascularization (TLR) at 1 year. BACKGROUND: Efficacy and safety data comparing biodegradable polymer BES with durable polymer cobalt-chromium EES are currently limited. METHODS: The NEXT trial is a prospective, multicenter, randomized, open-label, noninferiority trial comparing BES with EES. Between May and October 2011, 3,235 patients were randomly assigned to receive either BES (n = 1,617) or EES (n = 1,618). RESULTS: At 1 year, the primary efficacy endpoint of TLR occurred in 67 patients (4.2%) in the BES group, and in 66 patients (4.2%) in the EES group, demonstrating noninferiority of BES relative to EES (p for noninferiority <0.0001, and p for superiority = 0.93). Cumulative incidence of definite stent thrombosis was low and similar between the 2 groups (0.25% vs. 0.06%, p = 0.18). An angiographic substudy enrolling 528 patients (BES: n = 263, and EES: n = 265) demonstrated noninferiority of BES relative to EES regarding the primary angiographic endpoint of in-segment late loss (0.03 ± 0.39 mm vs. 0.06 ± 0.45 mm, p for noninferiority <0.0001, and p for superiority = 0.52) at 266 ± 43 days after stent implantation. CONCLUSIONS: One-year clinical and angiographic outcome after BES implantation was noninferior to and not different from that after EES implantation in a mostly stable coronary artery disease population. One-year clinical outcome after both BES and EES use was excellent, with a low rate of TLR and extremely low rate of stent thrombosis.

Effectiveness of the direct renin inhibitor, aliskiren, in patients with resistant hypertension.

Currently there is no consensus regarding which add-on therapy to use in resistant hypertension. We have conducted an open observational study of the use of aliskiren in resistant hypertensive patients. Forty-three patients with resistant hypertension were included in the study. The inclusion criteria were as follows: 1) office blood pressure (BP) > 140/90 mmHg despite treatment with at least three or more antihypertensive drugs; 2) no prior therapy with aliskiren; and 3) no renal insufficiency. Follow-up BP was determined at 1 and 3 months. Baseline BP was 153 ± 12/79 ± 12 mmHg. After 3 months, systolic BP (SBP) and diastolic BP (DBP) dropped significantly: 140 ± 19/73 ± 13 mmHg (P < 0.0001). Twenty-one patients (49%) had an office BP < 140/90 mmHg, and these patients were assigned to the good BP control group. Another 22 were placed into the poor BP control group. BP reductions from baseline in the good BP control group (SBP/ DBP: 19 ± 11/8 ± 7 mmHg) were larger than those in the poor BP control group (5 ± 15/3 ± 9 mmHg, P < 0.05). Mean BP (MBP) values at baseline, 1, and 3 months were higher in the poor BP control group. There was no significant difference in pulse pressure at baseline between the 2 groups. In multivariate analysis, only MBP at baseline correlated with lack of BP control. Aliskiren administration to resistant hypertensive patients was effective in reducing BP. The present findings suggest aliskiren may be useful as a fourth-line or fifth-line treatment added to other drugs in the treatment of resistant hypertension.

Lipocalin-type prostaglandin D synthase is associated with coronary vasospasm and vasomotor reactivity in response to acetylcholine.

BACKGROUND: Lipocalin-type prostaglandin D synthase (L-PGDS) catalyzes the biosynthesis of PGD(2), which acts as an anticoagulant, vasodilator, and inflammatory mediator. We examined the serum L-PGDS level, coronary macro- and microvasomotor functions, and their relationship in patients with chest pain and angiographically normal coronary arteries. METHODS AND RESULTS: The study included 96 patients who underwent diagnostic coronary angiography and had angiographically normal coronary arteries. Blood flow of the left anterior descending coronary artery (LAD) was analyzed by Doppler guidewire examination. Serum L-PGDS level was determined by ELISA. Infusion of acetylcholine (ACh) induced vasospasm of the LAD in all patients with vasospastic angina (VSA) (n=45), but in none of the patients without VSA (n=51). There were no significant differences in the baseline clinical characteristics of the nonVSA and VSA groups, except for the frequency of smoking. Serum L-PGDS level in the VSA group was significantly higher than that in the nonVSA group (77.1±4.4 vs. 63.9±2.5 µg/dl, P<0.01). Significant negative correlations were observed between the degree of LAD vasomotion in response to ACh and serum L-PGDS level (3 µg/min: r=-0.33; 10 µg/min: r=-0.35; 30 µg/min: r=-0.33, P<0.01). CONCLUSIONS: The L-PGDS level was elevated in patients with VSA and was associated with epicardial coronary vasomotion in response to ACh.

Whole-body periodic acceleration enhances brachial endothelial function.

BACKGROUND: Periodic acceleration in the direction of the spinal axis through repetitive movement increases the shear stress on the vascular endothelium. In the present study it was assessed whether whole-body periodic acceleration with a new device would enhance endothelial function in sedentary adult volunteers. METHODS AND RESULTS: Twenty-six sedentary subjects (44+/-3 years) were randomly assigned to remain sedentary or perform exercise training for 4 weeks, followed by crossover. Periodic acceleration was applied with a horizontal motion platform at 2-3 Hz and approximately +/-2.2 m/s2 for 45 min. Increases in the brachial artery diameter were examined at rest, during reactive hyperemia (flow-mediated dilatation: %FMD) and after sublingual administration of 0.3 mg nitroglycerin (%NTG) using high-resolution ultrasound. All subjects completed the study with no adverse side-effects. There were no significant changes in the resting heart rate or arterial pressure, body weight, or lipid profiles during the study. Although %FMD did not change during the non-training period with periodic acceleration, it significantly increased from 7.3+/-0.4% at baseline to 8.4+/-0.4% after the training period (p<0.05), while %NTG remained unchanged. CONCLUSIONS: Whole-body periodic acceleration with a horizontal motion platform improved vascular endothelial function in sedentary adults. This device might offer an alternative to active exercise for patients whose medical condition limits physical activity.

Impact of paraoxonase polymorphism (Q192R) on endothelial function in intact coronary circulation.

Paraoxonase-1 (PON1) can protect endothelial function by preventing the oxidation of low-density lipoprotein (LDL) cholesterol and retarding the development of atherosclerosis. We examined whether PON1 polymorphism influences endothelium-dependent coronary vasomotor responses. Sixty-seven patients underwent diagnostic cardiac catheterization, but showed no significant coronary artery stenosis. In all patients, PON1 genotypes (Q/Q, Q/R and R/R) were determined, and provocative testing was performed by the intracoronary administration of graded doses of bradykinin (BK; 0.2, 0.6 and 2.0 mug/min) and acetylcholine (ACh; 3, 10 and 30 mug/min). Coronary blood flow (CBF) was evaluated by a Doppler guide wire. The patients were divided into 2 groups on the basis of ACh testing: one with coronary spastic angina (CSA) and one with non-CSA. The frequencies of the PON1 genotype in the CSA group did not differ significantly from those in the non-CSA group. In the non-CSA group, the patients were subdivided into 2 groups: a group with the Q/Q or Q/R genotypes and a group with the R/R genotype. The vasoconstrictive responses of the epicardial coronary artery to ACh were comparable between the Q/Q + Q/R and R/R groups. Also, the coronary vasodilations induced by BK in the R/R group were similar to those in the QR + QQ group. There were no significant differences in the CBF responses induced by BK or ACh between the Q/Q + Q/R and R/R groups. In conclusion, as estimated by BK and ACh testing, our findings suggest that PON1 genotypes may not play a critical role in the modulation of endothelial vasomotor function in the intact coronary circulation.

The association between morning hypertension and metabolic syndrome in hypertensive patients.

Morning hypertension (MHT) and metabolic syndrome (MS) have been reported as important risk factors for stroke and cardiovascular events. We investigated the prevalence of MHT and MS among hypertensive patients in our outpatient clinic from June to August, 2005. We studied 181 hypertensive patients (91 men and 90 women) in our outpatient clinic using home-use electronic sphygmomanometers. Seventy-nine of these 181 patients (43.6%) demonstrated MHT, defined as systolic blood pressure (SBP) > or = 135 mmHg in the morning. Only 48.1% of the patients demonstrated normal SBP both at the clinic and in the morning at home, whereas 72.9% of the patients demonstrated normal diastolic blood pressure (DBP) under the same conditions. Sixty-one patients (33.7%) had MS, and 34 patients had both MHT and MS. Twenty-seven of the 102 patients (26.5%) without MHT had MS. The frequency of MS was significantly higher among those with MHT than those without MHT (p = 0.019). Multiple logistic regression analysis including smoking, alcohol consumption, sex, and age as confounding factors showed significant association between MHT and MS (odds ratio: 1.99; 95% confidence interval: 1.04-3.80; p = 0.039). In conclusion, although 1 year has passed since the JSH 2004 guidelines, 43.6% of our patients still showed MHT, and there was a significantly higher prevalence of MS among those with MHT. Our results suggest the need for a more vigorous intervention for controlling BP.

Brachial artery flow-mediated vasodilation is correlated with coronary vasomotor and fibrinolytic responses induced by bradykinin.

Endothelium plays a key role in the regulation of not only vascular tone but also thrombosis and fibrinolysis. Brachial flow-mediated vasodilation (FMD) provides a noninvasive method of assessing coronary endothelial dysfunction. However, no data are available on the relationship between brachial FMD and coronary fibrinolytic activity. Thus, we examined the relationship between brachial FMD and coronary vasomotor and fibrinolytic function. Brachial FMD by reactive hyperemia was defined as a change in diameter relative to the baseline as measured using high-resolution ultrasound. Coronary blood flow (CBF) responses to bradykinin (BK) were analyzed using Doppler flow velocity measurement. Coronary release of tissue-type plasminogen activator (tPA) antigen was determined as the transcardiac tPA gradient x [CBF x (100 - hematocrity 100)]. In 77 patients with normal coronary arteries, BK caused dose-dependent increases in CBF, transcardiac tPA gradient, and coronary tPA release. Among them, brachial FMD, the BK-induced CBF increase, and the coronary tPA release induced by BK in 14 diabetic subjects were lower than those in 63 non-diabetic subjects (p < 0.05, respectively). Brachial FMD correlated with the CBF increase, transcardiac tPA gradient (0.2 microg/min: r = 0.25; 0.6 microg/min: r = 0.43; 2.0 microg/min: r = 0.34; p < 0.05, respectively), and coronary tPA release (0.2 microg/min: r = 0.24; 0.6 microg/min: r = 0.44; 2.0 microg/min: r = 0.32; p < 0.05, respectively) in response to BK. Brachial FMD correlated significantly with coronary endothelial function and fibrinolytic activity in response to BK. Type 2 diabetes impaired coronary and brachial endothelium-dependent vasodilation and coronary fibrinolytic activity.

Plasma level of oxidized low-density lipoprotein is an independent determinant of coronary macrovasomotor and microvasomotor responses induced by bradykinin.

OBJECTIVES: We examined the relationship between coronary endothelium-dependent vasodilation in response to bradykinin (BK) and plasma levels of oxidized low-density lipoprotein (oxLDL) in subjects with normal coronary arteries. BACKGROUND: It is unclear whether the plasma oxLDL level is a determinant of coronary endothelial function. Bradykinin plays an important role in regulating resting coronary tone and flow-mediated coronary vasomotion. METHODS: Coronary blood flow (CBF) in the left anterior descending (LAD) coronary artery was assessed by quantitative angiography and a Doppler flow wire in 94 consecutive subjects with normal coronary arteries. The plasma oxLDL level was measured by enzyme-linked immunosorbent assay using DLH3R, a specific antibody against oxLDL. RESULTS: Plasma levels of oxLDL in diabetic subjects (n = 13) were higher than those in non-diabetic subjects (n = 81). Plasma levels of oxLDL correlated with body mass index (BMI). Bradykinin at doses of 0.2, 0.6, and 2.0 microg/min caused dose-dependent increases in diameter and CBF in the LAD coronary artery. By a univariate analysis, oxLDL levels significantly correlated with epicardial (r = -0.30, p < 0.0001) and resistant (r = -0.36, p = 0.003) coronary vasodilator responses to BK at 2.0 microg/min, whereas total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and triglycerides were not associated with these coronary responses. In a stepwise multivariate analysis, oxLDL levels were significantly correlated with epicardial and resistant coronary vasomotor responses to BK, independent of age, gender, smoking status, other lipid levels, BMI, hypertension, and diabetes. CONCLUSIONS: The plasma level of oxLDL is an appropriate surrogate for assessing coronary endothelial-dependent vasomotor function as estimated by responses to BK compared with conventional risk factors for atherosclerosis.

The relationship between flow-mediated brachial artery vasodilation and coronary vasomotor responses to bradykinin: comparison with those to acetylcholine.

Flow-mediated dilation (FMD) of brachial artery provides a noninvasive assessment of coronary endothelial dysfunction. Acetylcholine (ACh) has been used as an agent for estimating coronary endothelial function. In contrast to ACh, there is no evidence for a relationship between FMD and coronary vasodilation to bradykinin (BK). The aim of this study was to compare the flow-mediated vasodilation of brachial artery with coronary vasomotor responses to intracoronary ACh or BK in patients with an angiographically normal left anterior descending coronary artery. Ninety-one patients underwent the cardiac catheterization examination with coronary endothelial function testing and the brachial ultrasound study. BK (0.2, 0.6, 2.0 microg/min) and ACh (3, 10, 30 microg/min) were administered into the left coronary artery in a stepwise manner. Coronary blood flow was evaluated by the Doppler flow velocity measurement. Coronary diameters were measured by the quantitative coronary angiography. The assessment of endothelial function in the brachial artery was made in response to reactive hyperemia with high-resolution ultrasound. Bradykinin induced dose-dependent increases in epicardial coronary diameter and blood flow. There was a significant positive correlation between FMD- and BK-induced vasodilations of epicardial coronary arteries (0.2 microg/min: r = 0.30; 0.6 microg/min: r = 0.42; 2.0 microg/min: r = 0.44, P < 0.01, respectively) and resistance coronary arteries (0.2 microg/min: r = 0.40; 0.6 microg/min: r = 0.56; 2.0 microg/min: r = 0.59, P < 0.0001, respectively). FMD correlated with ACh-induced vasomotions of resistance but not epicardial coronary arteries. No correlation was seen between nitroglycerin-induced brachial artery vasodilation and BK-induced coronary vasodilation. The endothelial dysfunction of peripheral arteries correlated well with that of the coronary arteries especially vasomotor responses to BK.

Angiotensin-converting enzyme insertion/deletion polymorphism modulates coronary release of tissue plasminogen activator in response to bradykinin.

The aim of this study was to assess the relationship between the angiotensin converting enzyme gene (ACE) genotype and endothelium-dependent coronary vasomotor and fibrinolytic activity. The ACE DD genotype has been reported to be a risk factor for myocardial infarction. However, the mechanism is unknown. The fibrinolytic and renin-angiotensin systems are linked via ACE at the vascular beds. We studied 73 patients (II: n=24; ID: n=37; DD: n=12) who underwent diagnostic cardiac catheterization. Graded doses of bradykinin (BK) (0.2, 0.6, 2.0 microg/min) and acetylcholine (30,100 microg/min) were administered into the left coronary artery. Coronary blood flow (CBF) was evaluated by measuring Doppler flow velocity. Blood samples were taken from the aorta (Ao) and the coronary sinus (CS). Coronary release of tPA antigen was determined as a CS-Ao gradientXCBFX[(100-hematocrit) / 100]. ACE genotypes were determined using polymerase chain reaction. The ACE genotype did not appear to affect coronary macro- and microvascular responses induced by BK or acetylcholine. Coronary tissue plasminogen activator (tPA) release induced by BK was depressed in subjects with the ACE DD genotype. ACE levels in the DD genotype were significantly higher than those in the ID or II genotype. In all of the subjects, there was a significant negative correlation between the serum level of ACE activity and net coronary tPA release in response to BK at 0.6 microg/min. In conclusions, the DD genotype of the ACE gene impairs the coronary release of tPA induced by BK.

Endothelial modulation and tolerance development in the vasorelaxant responses to nitrate of rabbit aorta.

We investigated the endothelial modulations in nitrate tolerance in isolated rabbit aorta. Nitrate tolerance was induced by a 72-h treatment with transdermal nitroglycerin (NTG, 0.4 mg/h) in conscious rabbits, which was verified by a 20-fold increase in the EC50 values [NTG tolerance (6.1 +/- 0.8) x 10(-7) M vs control (3.0 +/- 0.6) x 10(-8) M]. The relaxations to NTG in tolerant and nontolerant aortic strips were enhanced when their endothelia were denuded [E(-)]. In the presence of endothelium [E(+)], NTG-tolerant vessels were not tolerant to acetylcholine (ACh), which can release endothelial nitric oxide (NO), exogenous NO or 8-bromo (Br)-cGMP. In NTG-tolerant and nontolerant vessels with endothelium, concentration-response curves for NO were the same as those in endothelium-absent tolerant vessels. In both NTG-tolerant and nontolerant vessels, treatment with superoxide dismutase (SOD, 20 units/ml), an O2-. scavenger, unaffected the responses to NTG reduced in the presence of endothelium, but treatment with NG-nitro-L-arginine methyl ester (L-NAME, 10(-4) M), an NO synthase (NOS) inhibitor, reversed these reductions. Thus, our data did not indicate that an increased endothelial superoxide O2-. production contributes to nitrate tolerance. Our study suggested that (i) an impaired biotransformation process from NTG to NO is responsible for the occurrence of nitrate tolerance and (ii) vascular response to NTG enhanced by endothelial removal is related to blocked endothelial NO release.