Effect of cutaneous nitroglycerin patches on coronary artery diameter: Issues concerning development of tolerance

AbstractThe coronary dilative and systemic responses to graded doses of intracoronary nitroglycerin were studied in 53 patients undergoing diagnostic coronary arteriography, 43 of whom had received a cutaneous nitroglycerin patch. During coronary arteriography, graded doses of 50, 100 and 200 μg of intracoronary nitroglycerin were given 5 min apart. An arteriogram and hemodynamic measurements were obtained after each dose. In the control group (n = 10) cumulative intracoronary nitroglycerin doses of 50,150 and 350 μg caused an increase in coronary diameter in the left anterior descending artery of 20 ± 4%, 21 ± 3% and 22 ± 7%, respectively, and in the circumflex artery of 18 ± 6%, 23 ± 8% and 18 ± 5% (p < 0.01 versus values in untreated group).In Group 1 (15 patients given a 5 mg/24 h nitroglycerin patch 2 to 12 h before coronary arteriography), the same intracoronary nitroglycerin doses increased the left anterior descending artery diameter by 6 ± 2%, 7 ± 2% and 7 ± 2%, respectively, and the circumflex artery diameter by 3 ± 2%, 3 ± 2% and 1 ± 3%. All values were statistically different from control (p < 0.05). An even more pronounced blunting (p < 0.01) of the coronary dilative response was observed in Group 2 (14 patients given a 15 mg/24 h nitroglycerin patch 2 to 12 h before arteriography). The diameter responses to intracoronary nitroglycerin observed in Group 3 (seven patients given a 5 mg/24 h nitroglycerin patch 24 h before arteriography) and Group 4 (seven patients given a 15 mg/24 h nitroglycerin patch 24 h before arteriography) were not significantly different from those of the control group.The results demonstrate that a nitroglycerin patch administered a few hours before coronary arteriography caused significant coronary artery dilation and that the incremental dilation due to the intracoronary nitroglycerin was small. On the other hand, 24 h after arteriography, the coronary dilative effect of the patch was attenuated (suggesting development of tolerance) and the increment in diameter induced by intracoronary nitroglycerin was much larger

Risk stratification for arrhythmic death in an emergency department cohort: a new method of nonlinear PD2i analysis of the ECG

Heart rate variability (HRV) reflects both cardiac autonomic function and risk of sudden arrhythmic death (AD). Indices of HRV based on linear stochastic models are independent risk factors for AD in postmyocardial infarction (MI) cohorts. Indices based on nonlinear deterministic models have a higher sensitivity and specificity for predicting AD in retrospective data. A new nonlinear deterministic model, the automated Point Correlation Dimension (PD2i), was prospectively evaluated for prediction of AD. Patients were enrolled (N = 918) in 6 emergency departments (EDs) upon presentation with chest pain and being determined to be at risk of acute MI (AMI) >7%. Brief digital ECGs (>1000 heartbeats, ∼15 min) were recorded and automated PD2i results obtained. Out-of-hospital AD was determined by modified Hinkle-Thaler criteria. All-cause mortality at 1 year was 6.2%, with 3.5% being ADs. Of the AD fatalities, 34% were without previous history of MI or diagnosis of AMI. The PD2i prediction of AD had sensitivity = 96%, specificity = 85%, negative predictive value = 99%, and relative risk >24.2 (p ≤ 0.001). HRV analysis by the time-dependent nonlinear PD2i algorithm can accurately predict risk of AD in an ED cohort and may have both life-saving and resource-saving implications for individual risk assessment

Repeatedly Northwards and Upwards: Southern African Grasslands Fuel the Colonization of the African Sky Islands in Helichrysum (Compositae)

The Afromontane and Afroalpine areas constitute some of the main biodiversity hotspots of Africa. They are particularly rich in plant endemics, but the biogeographic origins and evolutionary processes leading to this outstanding diversity are poorly understood. We performed phylogenomic and biogeographic analyses of one of the most species-rich plant genera in these mountains, Helichrysum (Compositae-Gnaphalieae). Most previous studies have focused on Afroalpine elements of Eurasian origin, and the southern African origin of Helichrysum provides an interesting counterexample. We obtained a comprehensive nuclear dataset from 304 species (≈50% of the genus) using target-enrichment with the Compositae1061 probe set. Summary-coalescent and concatenation approaches combined with paralog recovery yielded congruent, well-resolved phylogenies. Ancestral range estimations revealed that Helichrysum originated in arid southern Africa, whereas the southern African grasslands were the source of most lineages that dispersed within and outside Africa. Colonization of the tropical Afromontane and Afroalpine areas occurred repeatedly throughout the Miocene-Pliocene. This timing coincides with mountain uplift and the onset of glacial cycles, which together may have facilitated both speciation and intermountain gene flow, contributing to the evolution of the Afroalpine flora.This work received financial support from the Spanish Ministry of Science, Innovation and Universities (PID2019-105583GB-C22/AEI/10.13039/501100011033) and the Catalan government (“Ajuts a grups consolidats” 2021SGR00315 and FI grant to C.B.-G. 2022FI_B 00150). The Ph.D. thesis was carried out under the Ph.D. program “Plant Biology and Biotechnology” of the Autonomous University of Barcelona (UAB). Additional support was provided by the Czech Science Foundation GAČR project no. 20-10878S to R.S. and F.K. and long-term research development project (RVO 67985939) of the Czech Academy of Sciences. Additional funds were obtained from the Norwegian Programme for Development, Research and Higher Education (NUFU; project AFROALP-II, no 2007/1058) and the Research Council of Norway (project SpeciationClock, no 274607) to C.B.Abstract 1. Introduction 2. Materials and Methods 2.1. Taxon Sampling 2.2. DNA Extraction, Library Preparation, Target Capture, and Sequencing 2.3. Molecular Data Processing and Phylogenetic Analyses 2.4. Divergence Time Estimation 2.5. Ancestral Range Estimation 3. Results 3.1. Alignment Processing and Filtering 3.2. Phylogenetic Analyses 3.3. Divergence Time and Ancestral Range Estimation 3.4. Number, Type, and Directionality Estimation of Biogeographical Events 4. Discussion 4.1. Utility of Target-Enrichment Strategies in Reconstructing the Radiation of Helichrysum 4.2. The Early History of Helichrysum and Colonization of Madagascar 4.3. Repeatedly Northwards 4.4. Repeatedly Upwards 5. Conclusions Supplementary Materials Author Contributions Funding Data Availability Statement Acknowledgments Conflicts of Interest Reference

Coronary rotational atherectomy via transradial approach: A study using radial artery intravascular ultrasound

The use of coronary rotational atherectomy via radial artery (RA) has been limited because of the large diameter of guiding catheters. We studied the feasibility of this approach by sizing the RA by intravascular ultrasound (IVUS) and using 7 Fr (2.31 mm) guiding catheters. Seventeen transradial percutaneous transluminal coronary rotational atherectomy (PTCRA) procedures were performed in 16 patients, mean age 62 +/- 12 years, for a total of 19 vessels treated. The mean RA diameter was 2.9 +/- 0.36 mm and the mean reference diameter of the treated coronary vessels was 2.7 +/- 0.45 mm. The mean coronary percent stenosis was 74% +/- 10%, the mean minimum lumen diameter was 0.76 +/- 0.35 mm, and the mean lesion length was 16 +/- 19 mm. Ten vessels were treated with rotational atherectomy alone, or with adjunctive high pressure balloon angioplasty, achieving an acute lumen gain of 0.8 +/- 0.4 mm (P = 0.001). Nine arteries had stent implantation in addition to rotational atherectomy, resulting in an acute lumen gain of 2.4 +/- 0.5 mm (P = 0.001). The success rate was 94%. There were no vascular complications. Two patients had a non-Q myocardial infarction. In conclusion, transradial PTCRA when used in conjunction with IVUS of the RA is a safe and feasible procedure in selected cases. This may be an alternative approach of revascularization technique especially for patients with limited vascular access and for those who require early ambulation or early discharge from the hospital. Cathet. Cardiovasc. Intervent. 51: 234-238, 2000. (C) 2000 Wiley-Liss, Inc