Mild therapeutic hypothermia (32–36 °C) is associated with improved outcomes in patients with brain injury after cardiac arrest (CA). Various devices are available to induce and maintain hypothermia, ...but few studies have compared the performance of these devices. We performed a prospective study to compare four frequently used cooling systems in inducing and maintaining hypothermia followed by controlled rewarming.
We performed a prospective multi-centered study in ten ICU’s in three hospitals within the UPMC health system. Four different cooling technologies (seven cooling methods in total) were studied: two external water-circulating cooling blankets (Meditherm® and Blanketrol®), gel-coated adhesive cooling pads (Arctic Sun®), and endovascular cooling catheters with balloons circulating ice-cold saline (Thermogard®). For the latter system we studied three different types of catheter with two, three or four water-circulating balloons, respectively. In contrast to previous studies, we not only studied the cooling rate (i.e., time to target temperature) in the induction phase, but also the percentage of the time during the maintenance phase that temperature was on target ±0.5 °C, and the efficacy of devices to control rewarming. We believe that these are more important indicators of device performance than induction speed alone.
129 consecutive patients admitted after CA and treated with hypothermia were screened, and 120 were enrolled in the study. Two researchers dedicated fulltime to this study monitored TH treatment in all patients, including antishivering measures, additional cooling measures used (e.g. icepacks and cold fluid infusion), and all other issues related to temperature management. Baseline characteristics were similar for all groups. Cooling rates were 2.06 ± 1.12 °C/h for endovascular cooling, 1.49 ± 0.82 for Arctic sun, 0.61 ± 0.36 for Meditherm and 1.22 ± 1.12 for Blanketrol. Time within target range ±0.5 °C was 97.3 ± 6.0% for Thermogard, 81.8 ± 25.2% for Arctic Sun, 57.4 ± 29.3% for Meditherm, and 64.5 ± 20.1% for Blanketrol. The following differences were significant: Thermogard vs. Meditherm (p < 0.01), Thermogard vs. Blanketrol (p < 0.01), and Arctic Sun vs. Meditherm (p < 0.02). No major complications occurred with any device.
Endovascular cooling and gel-adhesive pads provide more rapid hypothermia induction and more effective temperature maintenance compared to water-circulating cooling blankets. This applied to induction speed, but (more importantly) also to time within target range during maintenance.
Background
Obesity is key feature of the metabolic syndrome and is associated with high cardiovascular morbidity and mortality. Obesity is associated with macrovascular endothelial dysfunction, a ...determinant of outcome in patients with coronary artery disease. Here, we compared the influence of obesity on microvascular endothelial function to that of established cardiovascular risk factors such as diabetes mellitus, hypertension, hypercholesterolemia, and smoking in patients with suspected coronary artery disease.
Methods and Results
Endothelial function was assessed during postocclusive reactive hyperemia of the brachial artery and downstream microvascular beds in 108 patients who were scheduled for coronary angiography. In all patients, microvascular vasodilation was assessed using peripheral arterial tonometry; laser Doppler flowmetry and digital thermal monitoring were performed. Body mass index was significantly associated with decreased endothelium‐dependent vasodilatation measured with peripheral arterial tonometry (r=0.23, P=0.02), laser Doppler flowmetry (r=0.30, P<0.01), and digital thermal monitoring (r=0.30, P<0.01). In contrast, hypertension, hypercholesterolemia, and smoking had no influence on microvascular vasodilatation. Especially in diabetic patients, endothelial function was not significantly reduced (control versus diabetes mellitus, mean±SEM or median interquartile range, peripheral arterial tonometry: 1.90±0.20 versus 1.67±0.20, P=0.19, laser Doppler flowmetry: 728% interquartile range, 427–1110 versus 589% interquartile range, 320–1067 P=0.28, and digital thermal monitoring: 6.6±1.0% versus 2.5±1.7%, P=0.08). In multivariate linear regression analysis, body mass index was the only risk factor that significantly attenuated endothelium‐dependent vasodilatation using all 3 microvascular function tests.
Conclusions
Higher body mass index is associated with reduced endothelial function in patients with suspected coronary artery disease, even after adjustment for treated diabetes mellitus, hypertension, hypercholesterolemia, and smoking.
Abstract
Aims
Patients with acute coronary syndrome who present initially with ST-elevation on the electrocardiogram but, subsequently, show complete normalization of the ST-segment and relief of ...symptoms before reperfusion therapy are referred to as transient ST-segment elevation myocardial infarction (STEMI) and pose a therapeutic challenge. It is unclear what the optimal timing of revascularization is for these patients and whether they should be treated with a STEMI-like or a non-ST-segment elevation myocardial infarction (NSTEMI)-like invasive approach. The aim of the study is to determine the effect of an immediate vs. a delayed invasive strategy on infarct size measured by cardiac magnetic resonance imaging (CMR).
Methods and results
In a randomized clinical trial, 142 patients with transient STEMI with symptoms of any duration were randomized to an immediate (STEMI-like) 0.3 h; interquartile range (IQR) 0.2–0.7 h or a delayed (NSTEMI-like) invasive strategy (22.7 h; IQR 18.2–27.3 h). Infarct size as percentage of the left ventricular myocardial mass measured by CMR at day four was generally small and not different between the immediate and the delayed invasive group (1.3%; IQR 0.0–3.5% vs. 1.5% IQR 0.0–4.1%, P = 0.48). By intention to treat, there was no difference in major adverse cardiac events (MACE), defined as death, reinfarction, or target vessel revascularization at 30 days (2.9% vs. 2.8%, P = 1.00). However, four additional patients (5.6%) in the delayed invasive strategy required urgent intervention due to signs and symptoms of reinfarction while awaiting angiography.
Conclusion
Overall, infarct size in transient STEMI is small and is not influenced by an immediate or delayed invasive strategy. In addition, short-term MACE was low and not different between the treatment groups.
The aim of this study was to analyse the relation between endothelial dysfunction (ED) and the occurrence of radial artery spasm (RAS) during transradial coronary procedures.
From May 2014 to June ...2015, endothelial function was assessed by EndoPAT and FMD before the procedure in 165 patients referred for coronary angiography or intervention. The primary endpoint was RAS, defined by patient's symptoms and procedural characteristics. The mean age of the study population was 63 years and 71% were male. In total 16% of the patients experienced RAS. The incidence of RAS did not differ between patients with and without ED (13.8% vs. 20.2%, OR 0.63, 95% CI: 0.25-1.58, p=0.32). The strongest predictors of RAS were a ratio of radial artery inner diameter and sheath outer diameter smaller than 1 (OR 4.7, 95% CI: 1.35-16.5, p=0.009) and a combination of clinical characteristics presented as an RAS risk score of at least 4 (p=0.007, OR 3.7, 95% CI: 1.37-9.89).
Endothelial dysfunction was not found to be a predictor of the occurrence of radial artery spasm in a cohort of patients undergoing elective heart catheterisation. Radial artery-sheath mismatch is the strongest pre-procedural predictor of RAS.
Percutaneous coronary intervention (PCI) of nonculprit vessels among patients with ST-segment elevation myocardial infarction (STEMI) is associated with improved clinical outcome compared with ...culprit vessel-only PCI. Fractional flow reserve (FFR) and coronary flow reserve are hyperemic indices used to guide revascularization. Recently, instantaneous wave-free ratio was introduced as a nonhyperemic alternative to FFR. Whether these indices can be used in the acute setting of STEMI continues to be investigated.
To assess the value of hemodynamic indices in nonculprit vessels of patients with STEMI from the index event to 1-month follow-up.
This substudy of the Reducing Micro Vascular Dysfunction in Revascularized STEMI Patients by Off-target Properties of Ticagrelor (REDUCE-MVI) randomized clinical trial enrolled 98 patients with STEMI who had an angiographic intermediate stenosis in at least 1 nonculprit vessel. Patient enrollment was between May 1, 2015, and September 19, 2017. After successful primary PCI, nonculprit intracoronary hemodynamic measurements were performed and repeated at 1-month follow-up. Cardiac magnetic resonance imaging was performed from 2 to 7 days and 1 month after primary PCI.
The value of nonculprit instantaneous wave-free ratio, FFR, coronary flow reserve, hyperemic index of microcirculatory resistance, and resting microcirculatory resistance from the index event to 1-month follow-up.
Of 73 patients with STEMI included in the final analysis, 59 (80.8%) were male, with a mean (SD) age of 60.8 (9.9) years. Instantaneous wave-free ratio (SD) did not change significantly (0.93 0.07 vs 0.94 0.06; P = .12) and there was no change in resting distal pressure/aortic pressure (mean SD, 0.94 0.06 vs 0.95 0.06; P = .25) from the acute moment to 1-month follow-up. The FFR decreased (mean SD, 0.88 0.07 vs 0.86 0.09; P = .001) whereas coronary flow reserve increased (mean SD, 2.9 1.4 vs 4.1 2.2; P < .001). Hyperemic index of microcirculatory resistance decreased and resting microcirculatory resistance increased from the acute moment to follow-up. The decrease in distal pressure from rest to hyperemia was smaller at the acute moment vs follow-up (mean SD, 10.6 11.2 mm Hg vs 14.1 14.2 mm Hg; P = .05). This blunted acute hyperemic response correlated with final infarct size (ρ, -0.29; P = .02). The resistive reserve ratio was lower at the acute moment vs follow-up (mean SD, 3.4 1.7 vs 5.0 2.7; P < .001).
In the acute setting of STEMI, nonculprit coronary flow reserve was reduced and FFR was augmented, whereas instantaneous wave-free ratio was not altered. These results may be explained by an increased hyperemic microvascular resistance and a blunted adenosine responsiveness at the acute moment that was associated with infarct size.
Eligible patients suffered at least 30 days earlier from an acute coronary syndrome (ACS), were free from ischemic or bleeding complications and reported regular intake of a dual antiplatelet therapy ...regimen. Assessment of endothelial function was obtained using pulse amplitude tonometry, which records digital pulse wave amplitude using fingertip plethysmography (EndoPAT, Itamar Medical, Caesarea, Israel) and quantifies the endothelium-mediated changes in vascular tone, elicited by a 5-min occlusion of the brachial artery. Ours is the third randomized trial to assess the off-target effects of ticagrelor on vascular function (3,4), yet it is the first extending the comparison of ticagrelor to both prasugrel and clopidogrel and the first multicenter trial being executed in a chronic setting (i.e., focusing on stabilized post-ACS patients).
The invasive microvascular function indices, coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR), exhibit a dynamic pattern after ST-segment-elevation myocardial ...infarction. The effects of microvascular injury on the evolution of the microvascular function and the prognostic significance of the evolution of microvascular function are unknown. We investigated the relationship between the temporal changes of CFR and IMR, and cardiovascular magnetic resonance-derived microvascular injury characteristics in reperfused ST-segment-elevation myocardial infarction patients, and their association with 1-month left ventricular ejection fraction and infarct size (IS).
In 109 ST-segment-elevation myocardial infarction patients who underwent angiography for primary percutaneous coronary intervention (PPCI) and at 1-month follow-up, invasive assessment of CFR and IMR were performed in the culprit artery during both procedures. Cardiovascular magnetic resonance was performed 2 to 7 days after PPCI and at 1 month and provided assessment of left ventricular ejection fraction, IS, microvascular obstruction, and intramyocardial hemorrhage.
CFR and IMR significantly changed over 1 month (both,
<0.001). The absolute IMR change over 1 month (ΔIMR) showed association with both microvascular obstruction and intramyocardial hemorrhage presence (both,
=0.01). ΔIMR differed between patients with/without microvascular obstruction (
=0.02) and with/without intramyocardial hemorrhage (
=0.04) but not ΔCFR for both. ΔIMR demonstrated association with both left ventricular ejection fraction and IS at 1 month (
<0.001,
=0.001, respectively), but not ΔCFR for both. Receiver-operating characteristics curve analysis of ΔIMR showed a larger area under the curve than post-PPCI CFR and IMR, and ΔCFR to be associated with both 1-month left ventricular ejection fraction >50% and extensive IS (the highest quartile).
In reperfused ST-segment-elevation myocardial infarction patients, CFR and IMR significantly improved 1 month after PPCI; the temporal change in IMR is closely related to the presence/absence of microvascular damage and IS. ΔIMR exhibits a stronger association for 1-month functional outcome than post-PPCI CFR, IMR, or ΔCFR.
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