GLP-1 vasodilatation in humans with coronary artery disease is not adenosine mediated.

BACKGROUND: Incretin therapies appear to provide cardioprotection and improve cardiovascular outcomes in patients with diabetes, but the mechanism of this effect remains elusive. We have previously shown that glucagon-like peptide (GLP)-1 is a coronary vasodilator and we sought to investigate if this is an adenosine-mediated effect. METHODS: We recruited 41 patients having percutaneous coronary intervention (PCI) for stable angina and allocated them into four groups administering a specific study-related infusion following successful PCI: GLP-1 infusion (Group G) (n = 10); Placebo, normal saline infusion (Group P) (n = 11); GLP-1 + Theophylline infusion (Group GT) (n = 10); and Theophylline infusion (Group T) (n = 10). A pressure wire assessment of coronary distal pressure and flow velocity (thermodilution transit time-Tmn) at rest and hyperaemia was performed after PCI and repeated following the study infusion to derive basal and index of microvascular resistance (BMR and IMR). RESULTS: There were no significant differences in the demographics of patients recruited to our study. Most of the patients were not diabetic. GLP-1 caused significant reduction of resting Tmn that was not attenuated by theophylline: mean delta Tmn (SD) group G - 0.23 s (0.27) versus group GT - 0.18 s (0.37), p = 0.65. Theophylline alone (group T) did not significantly alter resting flow velocity compared to group GT: delta Tmn in group T 0.04 s (0.15), p = 0.30. The resulting decrease in BMR observed in group G persisted in group GT: - 20.83 mmHg s (24.54 vs. - 21.20 mmHg s (30.41), p = 0.97. GLP-1 did not increase circulating adenosine levels in group GT more than group T: delta median adenosine - 2.0 ng/ml (- 117.1, 14.8) versus - 0.5 ng/ml (- 19.6, 9.4); p = 0.60. CONCLUSION: The vasodilatory effect of GLP-1 is not abolished by theophylline and GLP-1 does not increase adenosine levels, indicating an adenosine-independent mechanism of GLP-1 coronary vasodilatation. TRIAL REGISTRATION: The local research ethics committee approved the study (National Research Ethics Service-NRES Committee, East of England): REC reference 14/EE/0018. The study was performed according to institutional guidelines, was registered on http://www.clinicaltrials.gov (unique identifier: NCT03502083) and the study conformed to the principles outlined in the Declaration of Helsinki.

The role of Glucagon-Like Peptide 1 Loading on periprocedural myocardial infarction During elective PCI (GOLD-PCI study): A randomized, placebo-controlled trial.

BACKGROUND: The incretin hormone glucagon-like peptide 1 (GLP-1) has been shown to protect against lethal ischemia-reperfusion injury in animal models and against nonlethal ischemia reperfusion injury in humans. Furthermore, GLP-1 receptor agonists have been shown to reduce major adverse cardiovascular and cerebrovascular events (MACCE) in large-scale studies. We sought to investigate whether GLP-1 reduced percutaneous coronary intervention (PCI)-associated myocardial infarction (PMI) during elective PCI. METHODS: The study was a randomized, double-blind controlled trial in which patients undergoing elective PCI received an intravenous infusion of either GLP-1 at 1.2 pmol/kg/min or matched 0.9% saline placebo before and during the procedure. Randomization was performed in 1:1 fashion, with stratification for diabetes mellitus. Six-hour cardiac troponin I (cTnI) was measured with a primary end point of PMI defined as rise ≫×5 upper limit of normal (280 ng/L). Secondary end points included cTnI rise and MACCE at 12 months. RESULTS: A total of 192 patients were randomized with 152 (79%) male and a mean age of 68.1 ±â€¯8.9 years. No significant differences in patient demographics were noted between the groups. There was no difference in the rate of PMI between GLP-1 and placebo (9 [9.8%] vs 8 [8.3%], P = 1.0) or in the secondary end points of difference in median cTnI between groups (9.5 [0-88.5] vs 20 [0-58.5] ng/L, P = .25) and MACCE at 12 months (7 [7.3%] vs 9 [9.4%], P = .61). CONCLUSIONS: In this randomized, placebo-controlled trial, GLP-1 did not reduce the low incidence of PMI or abrogate biomarker rise during elective PCI, nor did it influence the 12-month MACCE rate which also remained low. CLINICAL TRIAL REGISTRATION: Clinicaltrials.gov Number: NCT02127996https://clinicaltrials.gov/ct2/show/NCT02127996.

Expansion and malapposition characteristics after bioresorbable vascular scaffold implantation.

OBJECTIVES: This study sought to investigate the postdeployment expansion and malapposition characteristics of the bioresorbable vascular scaffold (BVS) in real-world practice. BACKGROUND: The material construct of the BVS precludes overexpansion, with consequent potential for scaffold underexpansion and malapposition. In metallic stents, these features are associated with an increased risk of adverse events, including stent thrombosis. The postdeployment characteristics of the BVS are yet to be described outside clinical trials, where implantation occurred in straightforward lesion subsets. METHODS: Data from 25 patients undergoing BVS implantation were analyzed. Optical coherence tomography (OCT) was performed both before and after intervention to assess plaque composition, scaffold expansion and strut apposition. Manufacturer's compliance charts were used to predict expected minimal scaffold diameter and area. RESULTS: OCT pullback (522.2 mm) was analyzed. Overall, BVS achieved 82.5 ± 8.7 and 79.8 ± 12.3% of predicted minimal stent diameter and cross-sectional area (SCA), respectively, with expansion reduced in middle third of the scaffold (central SCA 76.7 ± 10.9% vs. noncentral SCA 81.5 ± 12.7%, P < 0.0001). Improved measures of SCA were observed with 1:1 balloon:vessel predilatation (1:1 PreD 82.8 ± 9.5% vs. No 1:1 PredD 78.6 ± 13.0%, P < 0.0001). Seven thousand six hundred scaffold struts were identified, of which 470 (6.18%) were malapposed. In fibrocalcific (FCa) plaques, malapposition was observed more frequently (FCa 44.4% vs. Other plaques 7.5%, P < 0.001) and at a greater distance from the vessel wall (FCa 0.17 ± 0.10 mm vs. Other plaques 0.14 ± 0.08 mm, P = 0.002). CONCLUSIONS: In this study, BVS expansion was significantly improved by 1:1 PreD, while increased rates of malapposition was associated with FCa plaques.

Coronary Flow Variations Following Percutaneous Coronary Intervention Affect Diastolic Nonhyperemic Pressure Ratios More Than the Whole Cycle Ratios.

Background Post-percutaneous coronary intervention (PCI) fractional flow reserve ≥0.90 is an accepted marker of procedural success, and a cutoff of ≥0.95 has recently been proposed for post-PCI instantaneous wave-free ratio. However, stability of nonhyperemic pressure ratios (NHPRs) post-PCI is not well characterized, and transient reactive submaximal hyperemia post-PCI may affect their precision. We performed this study to assess stability and reproducibility of NHPRs post-PCI. Methods and Results Fifty-seven patients (age, 63.77±10.67 years; men, 71%) underwent hemodynamic assessment immediately post-PCI and then after a recovery period of 10, 20, and 30 minutes and repeated at 3 months. Manual offline analysis was performed to derive resting and hyperemic pressure indexes (Pd/Pa resting pressure gradient, mathematically derived instantaneous wave-free ratio, resting full cycle ratio, and fractional flow reserve) and microcirculatory resistances (basal microvascular resistance and index of microvascular resistance). Transient submaximal hyperemia occurring post-PCI was demonstrated by longer thermodilution time at 30 minutes compared with immediately post-PCI; mean difference of thermodilution time was 0.17 seconds (95% CI, 0.07-0.26 seconds; P=0.04). Basal microcirculatory resistance was also higher at 30 minutes than immediately post-PCI; mean difference of basal microvascular resistance was 10.89 mm Hg.s (95% CI, 2.25-19.52 mm Hg.s; P=0.04). Despite this, group analysis confirmed no significant differences in the values of resting whole cycle pressure ratios (Pd/Pa and resting full cycle ratio) as well as diastolic pressure ratios (diastolic pressure ratio and mathematically derived instantaneous wave-free ratio). Whole cardiac cycle NHPRs demonstrated the best overall stability post-PCI, and 1 in 5 repeated diastolic NHPRs crossed the clinical decision threshold. Conclusions Whole cycle NHPRs demonstrate better reproducibility and clinical precision post-PCI than diastolic NHPRs, possibly because of less perturbation from predominantly diastolic reactive hyperemia and left ventricular stunning. Registration URL: https://clinicaltrials.gov/ct2/show/NCT03502083; Unique identifier: NCT03502083 and URL: https://clinicaltrials.gov/ct2/show/NCT03076476; Unique identifier: NCT03076476.

Adenosine-Induced Coronary Steal Is Observed in Patients Presenting With ST-Segment-Elevation Myocardial Infarction.

Background Adenosine is used to treat no-reflow in the infarct-related artery (IRA) during ST-segment-elevation myocardial infarction intervention. However, the physiological effect of adenosine in the IRA is variable. Coronary steal-a reduction of blood flow to the distal coronary bed-can occur in response to adenosine and this is facilitated by collaterals. We investigated the effects of adenosine on coronary flow reserve (CFR) in patients presenting with ST-segment-elevation myocardial infarction to better understand the physiological mechanism underpinning the variable response to adenosine. Methods and Results Pressure-wire assessment of the IRA after percutaneous coronary intervention was performed in 93 patients presenting with ST-segment-elevation myocardial infarction to calculate index of microvascular resistance, CFR, and collateral flow index by pressure. Modified collateral Rentrop grade to the IRA was recorded, as was microvascular obstruction by cardiac magnetic resonance imaging. Coronary steal (CFR <0.9), no change in flow (CFR=0.9-1.1), and hyperemic flow (CFR >1.1) after adenosine occurred in 19 (20%), 15 (16%), and 59 (63%) patients, respectively. Patients with coronary steal had higher modified Rentrop score to the IRA (1 [0, 1.75] versus 0 [0, 1], P<0.001) and a higher collateral flow index by pressure (0.25±0.10 versus 0.15±0.10, P=0.004) than the hyperemic group. The coronary steal group also had significantly higher index of microvascular resistance (61.68 [28.13, 87.04] versus 23.93 [14.67, 37.00], P=0.006) and had more disease (stenosis >50%) in the donor arteries (52.63% versus 22.03%, P=0.02) than the hyperemic group. Conclusions Adenosine-induced coronary steal may be responsible for a reduction in coronary flow reserve in a proportion of patients presenting with ST-segment-elevation myocardial infarction. Registration URL: https://www.clinicaltrials.gov; Unique identifier: NCT03145194. URL: https://www.isrctn.com; Unique identifier: ISRCTN3176727.

Mid-term clinical outcomes of ABSORB bioresorbable vascular scaffold implantation in a real-world population: A single-center experience.

BACKGROUND: Available data on the use of the ABSORB bioresorbable vascular scaffold (BVS) (Abbott Vascular, Santa Clara, CA) in real-world patients is limited. The aim of this study was to assess the mid-term clinical outcomes in a real-world population treated with ABSORB BVS. METHODS AND MATERIALS: We retrospectively evaluated all patients treated with ABSORB at Papworth Hospital, Papworth Everard, UK between July 2012 and July 2014. A total of 108 patients (126 lesions) were identified. Clinical follow-up was performed on all subjects by clinic visit or telephone interview. RESULTS: Most patients were male (91.7%) with a relative high incidence of previous myocardial infarction (MI) (40.7%). Clinical presentation was equally divided between stable angina and acute coronary syndrome (ACS) (51.8% vs. 48.2%, p=0.59). Of the ACS patients, 26.9% presented with ST-elevation myocardial MI. Intravascular imaging was used in all cases. Predilatation (92.9%) and postdilatation (82.5%) were frequently performed. Major adverse cardiac event (MACE) rates defined as the composite of all-cause death, follow-up MI and target vessel revascularization were 2.5% at 6-month and 4.5% at 1-year. The 1-year target lesion failure rate, defined as the composite of cardiac death, target-vessel MI and target lesion revascularization was 1.9%. There was 1 case of subacute stent thrombosis. CONCLUSIONS: The use of ABSORB BVS in real-world patients appears to be associated with good mid-term clinical outcomes when guided by intravascular imaging. Larger studies are required to evaluate further the role of BVS in routine clinical practice and examine how this compares to metallic devices. SUMMARY: Available data on the use of the ABSORB BVS in real-world patients is limited. We retrospectively evaluated all patients treated with ABSORB BVS between July 2012 and July 2014. A total of 108 patients (126 lesions) were identified. Clinical presentation was equally divided between stable angina and acute coronary syndrome (51.8% vs. 48.2%, p=0.59). Predilatation (92.9%) and postdilatation (82.5%) were frequently performed. Estimated MACE rates at 6-month and 1-year were 2.5% and 4.5% respectively, with a 1-year TLF rate of 1.9%. These results suggest that the use of ABSORB BVS use in the real-world is associated with good mid-term clinical outcomes when guided by intravascular imaging.