The effect of fresh versus standard blood transfusion on microvascular endothelial function.

BACKGROUND: The duration of red blood cell (RBC) storage may have a negative impact on endothelial nitric oxide bioavailability. We tested the hypothesis that transfused fresh blood will have a more favorable effect on microvascular endothelial function as compared to older standard issue blood. METHODS: Participants requiring chronic RBC transfusions were enrolled in a crossover design study to receive fresh (<7 days of storage) or standard (up to 42 days of storage) blood on 2 separate visits. Endothelial function was assessed by reactive hyperemia peripheral arterial tonometry that was measured before and after transfusions. For each participant, the difference between endothelial function pretransfusion and posttransfusion was assessed in relation to blood storage time. RESULTS: Twenty-one patients (71 ± 16 years, 52% females) were enrolled. Mean age of fresh blood was 5.5 days (±1.0), and that of standard blood was 24.5 days (±7.9 days). The pretransfusion hemoglobin was 83.1 ± 2.5 g/L; and posttransfusion, 98.9 ± 2.6 g/L. An average of 2 U of packed RBCs was transfused. Microvascular endothelial function decreased more frequently after transfusion of standard blood compared to fresh blood. Standard issue blood transfusion was associated with decrease in reactive hyperemia peripheral arterial tonometry index (-0.25 ± 0.63) compared to fresh blood (+0.03 ± 0.49); P = .026. CONCLUSION: Transfusions of standard issue blood are associated with less favorable effect on microvascular endothelial function as compared to fresh blood.

The Impact of Peripheral Nerve Stimulation on Coronary Blood Flow and Endothelial Function.

PURPOSE: The geko™ device is a small transcutaneous nerve stimulator that is applied non-invasively to the skin over the common peroneal nerve to stimulate peripheral blood flow. The purpose of this study was to investigate the effect of peripheral nerve stimulation on coronary flow dynamics and systemic endothelial function. METHODS: We enrolled 10 male patients, age 59 ± 11 years, with symptomatic obstructive coronary disease undergoing percutaneous coronary intervention (PCI). Coronary flow dynamics were assessed invasively using Doppler flow wire at baseline and with nerve stimulation for 4 min. Measurements were taken in the stenotic coronary artery and in a control vessel without obstructive disease. At a separate visit, peripheral blood flow at the popliteal artery (using duplex ultrasound assessment) and endothelial function assessed by peripheral artery tonometry (PAT) were measured at baseline and after one hour of nerve stimulation. RESULTS: Compared to baseline, there was a significant increase in coronary blood flow as measured by average peak velocity (APV) in the control vessel with nerve stimulation (20.3 ± 7.7 to 23.5 ± 10 cm/s; p = 0.03) and non-significant increase in the stenotic vessel (21.9 ± 12 to 23.9 ± 12.9 cm/s; p = 0.23). Coronary flow reserve did not change significantly. Reactive hyperemia-peripheral arterial tonometry (Rh-PAT) increased from 2.28 ± 0.39 to 2.67 ± 0.6, p = 0.045. CONCLUSIONS: A few minutes of peripheral nerve stimulation may improve coronary blood flow. This effect is more prominent in non-stenotic vessels. Longer stimulation improved endothelial function.

Long-term outcome following remote ischemic postconditioning during percutaneous coronary interventions-the RIP-PCI trial long-term follow-up.

The clinical value of ischemic conditioning during percutaneous coronary intervention (PCI) and mode of administration is controversial. Our aim was to assess the long-term effect of remote ischemic postconditioning among patients undergoing PCI. We randomized 360 patients undergoing PCI who presented with a negative troponin T at baseline into 3 groups: 2 groups received remote ischemic postconditioning (with ischemia applied to the arm in 1 group and to the thigh in the other group), and the third group acted as a control group. Remote ischemic postconditioning was applied during PCI immediately following stent deployment, by 3, 5-minute cycles of blood pressure cuff inflation to >200 mm Hg on the arm or thigh (20 mm Hg to the arm in the control), with 5-minute breaks between each cycle. There were no differences in baseline characteristics among the 3 groups. Periprocedural myocardial injury occurred in 33% (P = 0.64). After 1 year, there was no difference between groups in death (P = 0.91), myocardial infarction (P = 0.78), or repeat revascularization (P = 0.86). During 3 years of follow-up, there was no difference in death, myocardial infarction, and revascularization among the groups (P = 0.45). Remote ischemic postconditioning during PCI did not affect long-term cardiovascular outcome. A similar effect was obtained when remote ischemia was induced to the upper or lower limb. ClinicalTrials.gov Identifier: NCT00970827.

Nitroglycerin-Derived Pd/Pa for the Assessment of Intermediate Coronary Lesions.

OBJECTIVES: To assess the predictive value of Pd/Pa after nitroglycerin administration (Pd/Pa[N]) as compared with standard fractional flow reserve (FFR). METHODS: Consecutive patients with intermediate coronary lesions assessed by FFR between January 2014 and October 2015 were included. We measured Pd/Pa at baseline, Pd/Pa(N), and Pd/Pa after incremental doses of intracoronary adenosine. RESULTS: A total of 134 patients (27% females; mean age, 65 years) were included. The diagnostic performance of Pd/Pa(N) and identification of cut-off value for Pd/Pa(N) compared with FFR threshold of 0.8 using receiver-operating characteristic (ROC) area under the curve analysis was between 0.98 (95% confidence interval, 0.95-1.00; P<.05) for 48 µg and 0.86 (95% confidence interval, 0.79-0.94; P<.05) for 240 µg adenosine. Pd/Pa(N) ≤0.8 had 100% positive predictive value. Pd/Pa(N) ≥0.94 provided 100% negative predictive value with a high sensitivity (>92%). Optimal diagnostic accuracy of Pd/Pa(N) was achieved for values ≤0.84. The Pearson's correlation between Pd/Pa(N) and FFR varied between 0.89 for 24 µg adenosine and 0.77 for 240 µg (P<.01). CONCLUSION: Pd/Pa(N) values can be used for diagnosis of hemodynamically significant lesions. Pd/Pa(N) correlates well with standard FFR. Pd/Pa(N) cut-off of ≤0.8 can be considered significant without need for adenosine injection. The value of using adenosine whenever Pd/Pa(N) is ≥0.94 is limited.

Randomized Trial of Compression Duration After Transradial Cardiac Catheterization and Intervention.

BACKGROUND: Radial artery occlusion is a known complication following transradial cardiac catheterization. A shorter duration of postprocedural radial clamp time may reduce radial artery occlusion (RAO) but might be associated with incomplete hemostasis. METHODS AND RESULTS: In total, 568 patients undergoing transradial diagnostic cardiac catheterization were randomly assigned to either 20 minutes (ultrashort) or 60 minutes (short) hemostatic compression time using patent hemostasis. Subsequently, clamp pressure was reduced gradually over 20 minutes. Access site hemostasis and RAO were assessed after clamp removal. Repeated assessment of RAO was determined at 1 week in 210 (37%) patients. Mean age was 64±11 years, and 30% were female. Percutaneous coronary intervention was performed in 161 patients. RAO immediately after clamp removal was documented in 14 (4.9%) and 8 (2.8%) patients in the 20- and 60-minute clamp application groups, respectively (P=0.19). The incidence of grade 1 hematoma was higher in the 20-minute group (6.7% versus 2.5%, P=0.015). RAO at 1 week after the procedure was 2.9% and 0.9% in the 20- and 60-minute groups, respectively (P=0.36). Requirement for clamp retightening (36% versus 16%, P=0.01) was higher among patients who had RAO. Need for clamp retightening was the only independent predictor of RAO (P=0.04). CONCLUSIONS: Ultrashort radial clamp application of 20 minutes is not preferable to a short duration of 60 minutes. The 60-minute clamp duration is safe and provides good access site hemostasis with low RAO rates. CLINICAL TRIAL REGISTRATION: URL: http://www.clinicaltrials.gov. Unique identifier: NCT02269722.

Association of endothelial dysfunction and no-reflow during primary percutaneous coronary intervention for ST-elevation myocardial infarction.

BACKGROUND: Coronary no-reflow during primary percutaneous coronary intervention (PPCI) is a predictor of poorer cardiovascular outcome. Both endothelial dysfunction and no-reflow involves abnormal vascular function and hemostasis. Our aim was to assess the association between endothelial dysfunction and no reflow during primary PCI. METHODS: Thirty consecutive patients with ST elevation myocardial infarction (STEMI) and normal flow during primary PCI were compared to 19 consecutive patients who had no reflow. All subjects underwent assessment of peripheral endothelial function by reactive hyperemia index (RHI) 48-72h post PCI using the EndoPAT device. RESULTS: Age, sex and hypertension were similar in both groups. Smokers were less likely to have no-reflow. Post PPCI there was less ST segment resolution in the no-reflow group (48%±7 vs. 81%±6; p=0.001). Patients who had no reflow had subsequently lower ejection fraction (39%±10 vs. 47%±10; p=0.015). There was no difference in vascular function (RHI), between the no-reflow and normal flow groups (1.91±0.3 vs. 2.09±0.11; p=0.24). CONCLUSIONS: Systemic peripheral endothelial function does not differ between STEMI patients with and without no reflow during primary PCI.