Administration Of Nitroglycerin Research Articles

Efficacy of Continuous Transdermal Nitroglycerin for Treating Hot Flashes by Inducing Nitrate Cross-tolerance in Perimenopausal and Postmenopausal Women

Due to the potential risks of long-term systemic estrogen therapy, many menopausal women are interested in nonhormonal treatments for vasomotor symptoms. Physiologic studies indicate that nitric oxide plays a key role in mediating hot flash-related vasodilation, suggesting that nonhormonal medications that induce nitrate tolerance in the vasculature may offer therapeutic benefit for vasomotor symptoms. To determine whether uninterrupted administration of transdermal nitroglycerin (NTG) to induce nitrate cross-tolerance decreased the frequency or severity of menopause-related hot flashes. This randomized, double-blinded, placebo-controlled clinical trial included perimenopausal or postmenopausal women reporting 7 or more hot flashes per day who were recruited from northern California by study personnel at a single academic center. Patients were randomized between July 2017 and December 2021, and the trial ended in April 2022 when the last randomized participant completed follow-up. Uninterrupted daily use of transdermal NTG (participant-directed dose titration from 0.2-0.6 mg/h) or identical placebo patches. Validated symptom diaries assessing changes in any hot flash frequency (primary outcome) and moderate-to-severe hot flash frequency over 5 and 12 weeks. Among the 141 randomized participants (70 NTG [49.6%], 71 placebo [50.4%]; 12 [85.8%] Asian, 16 [11.3%] Black or African American, 15 [10.6%] Hispanic or Latina, 3 [2.1%] multiracial, 1 [0.7%] Native Hawaiian or Pacific Islander, and 100 [70.9%] White or Caucasian individuals), a mean (SD) of 10.8 (3.5) hot flashes and 8.4 (3.6) moderate-to-severe hot flashes daily was reported at baseline. Sixty-five participants assigned to NTG (92.9%) and 69 assigned to placebo (97.2%) completed 12-week follow-up (P = .27). Over 5 weeks, the estimated change in any hot flash frequency associated with NTG vs placebo was -0.9 (95% CI, -2.1 to 0.3) episodes per day (P = .10), and change in moderate-to-severe hot flash frequency with NTG vs placebo was -1.1 (95% CI, -2.2 to 0) episodes per day (P = .05). At 12 weeks, treatment with NTG did not significantly decrease the frequency of any hot flashes (-0.1 episodes per day; 95% CI, -1.2 to 0.4) or moderate-to-severe hot flashes (-0.5 episodes per day; 95% CI, -1.6 to 0.7) relative to placebo. In analyses combining 5-week and 12-week data, no significant differences in change in the frequency of any hot flashes (-0.5 episodes per day; 95% CI, -1.6 to 0.6; P = .25) or moderate-to-severe hot flashes (-0.8 episodes per day; 95% CI, -1.9 to 0.2; P = .12) were detected with NTG vs placebo. At 1 week, 47 NTG (67.1%) and 4 placebo participants (5.6%) reported headache (P < .001), but only 1 participant in each group reported headache at 12 weeks. This randomized clinical trial found that continuous use of NTG did not result in sustained improvements in hot flash frequency or severity relative to placebo and was associated with more early but not persistent headache. Clinicaltrials.gov Identifier: NCT02714205.

ARTERIAL BAROREFLEX FUNCTION IS IMPAIRED DURING THE RECOVERY FROM ACUTE LUNG INJURY IN A BLEOMYCIN-INDUCED RAT LUNG INJURY MODEL

Objective: Acute lung injury (ALI) and its clinical correlate, the acute respiratory distress syndrome (ARDS), results due, in part, to disruption of the normal capillary endothelial barrier and invokes perturbations of ventilatory control. ALI is associated with autonomic dysfunction and cardiac arrhythmias. In a recent study we suggested that rats were susceptible to cardiac arrhythmia even during the recovery from ALI, in part, due to abnormalities in cardiac sympathetic ganglia. On the other hand, if arterial baroreflex function is altered during the recovery of ALI remains unknown. The primary goal of this study was to examine baroreflex function during the recovery stage from ALI in a bleomycin (Bleo)-induced rat ALI model. Design and method: ALI was induced in male SD rats (200-250g) using a single intra-tracheal injection of Bleo (2.5 mg/kg). 4 weeks post Bleo (n = 7) or saline (sham, n = 6), rats were anesthetized with urethane (800 mg/kg ip) and alpha-chloralose (40 mg/kg ip) to measure baroreflex sensitivity. Baroreflex curves were generated by measuring the heart rate (HR) and renal sympathetic nerve activity (RSNA) responses to decreases and increases in mean blood pressure (MAP) by intravenous administration of nitroglycerin (25 μg) followed by phenylephrine (10 μg). Differences between sham and Bleo rats were determined by one-way ANOVA followed by the Tukey post hoc test. Results: Compared to sham rats, there was a significant decrease in the RSNA (117.4±11.6 vs. 77.5±8.9 %baseline, P = 0.018) or HR (147.5±9.7 vs. 75.1±11.3 bpm, P&lt;0.001) range in Bleo rats. Minimum RSNA or HR was also decreased in bleo rats compared to sham rats. There was no significant difference in either the slope coefficient or the blood pressure at the midpoint of the range (BP50) between the two groups. There was a significant decrease in peak slope [or maximum gain (Gainmax) in Bleo rats (MAP-RSNA Gainmax: 3.11±0.27 vs. 1.74±0.31, p = 0.017; MAP-HR Gainmax: 3.57±0.31 vs. 1.21±0.14, p&lt;0.001). Conclusions: Our data demonstrate impaired baroreflex function during the recovery state from ALI. Autonomic dysfunction may also contribute to increased cardiovascular risk during the recovery stage from ALI.

Nitroglycerin improves the visibility of fibula-free flap perforators on computed tomography angiography in patients with oral or maxillofacial lesion

PurposeTo investigate the improvement of image quality and visualization of fibula-free flap (FFF) perforators on computed tomography angiography (CTA) after administration of sublingual nitroglycerin (NTG) tablets. MethodsA total of 60 patients with oral or maxillofacial lesions before CTA of the lower extremity were randomly divided into two groups (NTG group and non-NTG group). The signal-to-noise ratio (SNR) and contrast-to-noise ratio (CNR), overall image quality and grading of vessels were evaluated and compared. The lumen diameters of the major arteries and the proximal and distal peroneal perforators were measured. The number of visible perforators in muscular clearance and muscular layer was also counted and compared between the two groups. ResultsThe CNR of posterior tibial artery and overall image quality of CTA images in the NTG group was significantly higher than that in the non-NTG group (p < 0.05), although the SNR and CNR of other arteries did not show significant differences (p > 0.05). The lumen diameters of the peroneal artery and its perforators, anterior tibial artery, and posterior tibial artery were significantly larger in the NTG group (p < 0.001), while no significant difference prevailed in the diameter of the popliteal artery between the two groups (p = 0.298). Compared with the non-NTG group, a significant increase in the number of visible perforators was noted in the NTG group (p < 0.001). ConclusionsThe administration of sublingual NTG in CTA of the lower extremity can improve the image quality and visualization of perforators, which aids to surgeons select the optimum FFF.

Characterization of the biochemical and behavioral effects of cannabidiol: implications for migraine

Cannabidiol (CBD) is the main pharmacologically active phytocannabinoid. CBD exerts an analgesic effect in several pain models, does not have side effects and has low toxicity. The data about CBD mechanisms of action in pain and its therapeutic potential in this area are limited. Here, we tested CBD effects in animal models specific for migraine. We assayed CBD distribution in plasma and in cranial areas related to migraine pain in male Sprague Dawley rats treated chronically (5 days). Successively, we tested CBD activity on the behavioral and biochemical effects induced in the acute and the chronic migraine animal models by nitroglycerin (NTG) administration. In the acute migraine model, rats received CBD (15 mg or 30 mg/kg, i.p) 3 h after NTG (10 mg/kg i.p.) or vehicle injection. In the chronic migraine model, rats were treated with CBD and NTG every other day over nine days with the following doses: CBD 30 mg/kg i.p., NTG 10 mg/kg i.p. We evaluated behavioral parameters with the open field and the orofacial formalin tests. We explored the fatty acid amide hydrolase gene expression, cytokines mRNA and protein levels in selected brain areas and CGRP serum level. CBD levels in the meninges, trigeminal ganglia, cervical spinal cord, medulla pons, and plasma were higher 1 h after the last treatment than after 24 h, suggesting that CBD penetrates but does not accumulate in these tissues. In the acute model, CBD significantly reduced NTG-induced trigeminal hyperalgesia and CGRP and cytokine mRNA levels in peripheral and central sites. In the chronic model, CBD caused a significant decrease in NTG-induced IL-6 protein levels in the medulla–pons, and trigeminal ganglion. It also reduced CGRP serum levels. By contrast, CBD did not modulate TNF-alpha protein levels and fatty acid amide hydrolase (FAAH) gene expression in any of investigated areas. In both experimental conditions, there was no modulation of anxiety, motor/exploratory behavior, or grooming. These findings show that CBD reaches brain areas involved in migraine pain after systemic administration. They also show for the first time that CBD modulates migraine-related nociceptive transmission, likely via a complex signaling mechanism involving different pathways.

Evaluation of Vasodilatory Effect of Nitroglycerin in Cardioplegia Solution on Patients Undergoing Coronary Artery Bypass Graft Surgery.

This study aimed to evaluate the vasodilatory effect of nitroglycerin (NTG) in cardioplegia solution on changes in troponin I and creatine phosphokinase-MB (CPK-MB) levels during coronary artery bypass graft (CABG) surgery. A randomized controlled double-blind clinical trial was performed on 44 patients who were candidates for CABG surgery. These patients were divided into two groups. In the first group (NTG group), 3 mg/kg NTG was added to the cardioplegia solution, while 10 cc placebo (distilled water) was added to the cardioplegia solution in the second group (control group). Troponin I and CPK-MB levels were then assessed before and after the surgery. In this study, 72.7% and 27.3% of patients in the NTG group and 68.2% and 31.8% of patients in the control group were male and female, respectively. In addition, 9.1% within the age range of 40-50 years, 27.3% within the age range of 50-60 years, and 63.6% within the age range of more than 60 years were present in the NTG group. Moreover, 18.2% within the age range of 40-50 years, 36.4% within the age range of 50-60 years, and 45.5% within the age range of more than 60 years were present in the control group. Although the mean cardiopulmonary bypass (CPB) and cross-clamp time was insignificantly higher in the NTG group compared to the control group. In addition, troponin I and CPK-MB levels after surgery in the NTG group with the mean of 2090.68 ± 1856.07 and 97.27 ± 38.17 were significantly lower than those of the control group with the mean of 2697.02 ± 5586.56 and 137.95 ± 227.99, respectively (P-value <0.05). According to the results of this study, although troponin I and CPK-MB levels increased significantly after CABG surgery, this increase was significantly lower in the intervention group compared to the control group following the administration of NTG.

PO-04-005 LEFT CIRCUMFLEX ARTERY VASOSPASM DURING PULSED FIELD ABLATION AT THE MITRAL ISTHMUS: CHARACTERIZATION OF TIME-TO-RESOLUTION

While pulsed field ablation (PFA) has emerged as a novel energy modality for ablation of atrial arrhythmias and is accompanied by a theoretically safer profile given its tissue selectivity and sparing of collateral structures, a recent study has highlighted the occurrence of subtotal coronary vasospasm during atrial fibrillation (AF) ablation on the cavo-tricuspid isthmus with PFA. While these observations were subclinical, there is at least one case report of left circumflex (LCx) coronary artery vasospasm during PFA at the mitral isthmus (MI) during AF ablation. To evaluate the natural history time-to-resolution of coronary vasospasm of the LCx artery during PFA at the MI. In a prospective, consecutively enrolled cohort of patients receiving AF ablation under deep sedation, diagnostic coronary angiography was performed via right femoral arterial access before, during, and after ablation on the MI with a multi-spline PFA catheter (Farawave, Boston Scientific Inc). LCx spasm was identified, characterized by severity, and monitored for progression and time-to-resolution. A total of 19 patients underwent PFA on the lateral MI with successful bidirectional block. Notably, 7 patients (37%) developed LCx vasospasm during ablation, of which 3 cases were mild (<50% decrease in luminal diameter), 2 were moderate (50 to 90% decrease), and 2 were severe (>90% decrease). All of the mild and moderate spasm occurrences self-resolved, with mild spasm taking on average 5.7 minutes to be relieved, and moderate spasm requiring 5 minutes. Relief of severe spasm required an average of 15 minutes, with both necessitating administration of intracoronary or intravenous nitroglycerin. Electrocardiographic ST changes were only present in one case of severe spasm (which resolved with relief of spasm), and there were no hemodynamic changes during spasm. As PFA becomes an alternative to radiofrequency and cryothermal ablation, it behooves operators to be vigilant for vasospastic effects on adjacent coronary vessels during ablation. Further investigation with larger populations is required to more fully elucidate the injurious potential of PFA-induced coronary vasospasm. This study is one of the first to elaborate on the features of LCx vasospasm during PFA on the MI.Tabled 1Patient CharacteristicsAge, mean±SD, y65.6±10.1Male, n (%)14 (74)Body mass index, mean±SD30.3±4.9Medical HistoryType of atrial fibrillationParoxysmal, n (%)4 (21)Persistent, n (%)15 (79)Duration of atrial fibrillation, mean±SD, months48.2±66.4CHA2DS2-VASc Score, mean±SD2.1±1.4Hypertension, n (%)13 (68)Diabetes, n (%)4 (21)Dyslipidemia, n (%)11 (58)Sleep apnea, n (%)1 (5)Prior stroke or transient ischemic attack, n (%)2 (11)Coronary artery disease, (%)4 (21)Congestive heart failure, n (%)1 (5)Left ventricular ejection fraction, mean±SD, %62.3±3.4Left atrium dimension, mean±SD, mm45.8±9.2MedicationsWarfarin, n (%)12 (63)Non-Warfarin oral anticoagulant, n (%)7 (37)Antiarrhythmic drugs, n (%)Class I7 (37)Class II11 (58)Class III5 (26)Class IV0 (0) Open table in a new tab

Effects of Nitric Oxide on the Activity of P2X and TRPV1 Receptors in Rat Meningeal Afferents of the Trigeminal Nerve.

Nitric oxide is one of the endogenous molecules that play a key role in migraine. However, the interaction between NO and the main players in the nociceptive activity of the meningeal trigeminal afferents-TRPV1 and P2X3 receptors-remains unstudied. In the current project, the effects of acute and chronic NO administration on the activity of TRPV1 and P2X3 receptors in the peripheral afferents were studied using electrophysiological recording of action potentials of the trigeminal nerve in the rat hemiskull preparations. The data obtained indicate that exogenous and endogenous NO increased the activity of the trigeminal nerve independent on the inhibition of the TRPV1 and P2X3 receptors. The activity of the trigeminal nerve triggered by ATP changed neither in acute incubation in the NO donor-sodium nitroprusside (SNP) nor in the chronic nitroglycerine (NG)-induced migraine model. Moreover, the chronic NG administration did not increase in the number of degranulated mast cells in the rat meninges. At the same time, the capsaicin-induced activity of the trigeminal nerve was higher with chronic NO administration or after acute NO application, and these effects were prevented by N-ethylmaleimide. In conclusion, we suggested that NO positively modulates the activity of TRPV1 receptors by S-nitrosylation, which may contribute to the pro-nociceptive action of NO and underlie the sensitization of meningeal afferents in chronic migraine.

Post-partum myocardial ischemia due to intramuscular methylergonovine-induced coronary vasospasm: case report

BackgroundMethylergonovine is a vasoconstrictive agent historically used as a provocative agent in the lab for coronary vasospasm; it is also a first line uterotonic agent for management of postpartum hemorrhage.Case PresentationA 29-year-old female with history of smoking and idiopathic thrombocytopenia received intramuscular methylergonovine after delivery of twins for intrauterine hemorrhage management. Subsequently, she had episodes of chest pain with high sensitivity Troponin I elevation to 1509 ng/L with accompanying septal T wave inversions, decreased left ventricular ejection fraction to 49% and basal septal wall hypokinesis. Computed tomography (CT) coronary angiogram showed patent coronary arteries and no coronary arterial dissection. The patient was conservatively managed with aspirin and metoprolol, and on follow up had fully recovered left ventricular function with resolution of wall motion abnormalities. Given this, coronary vasospasm due to intramuscular methylergonovine is the most likely cause of patient’s chest pain and associated myocardial ischemia.ConclusionsIntramuscular, intrauterine, intravenous, and even oral methylergonovine can rarely cause coronary vasospasm leading to myocardial ischemia. Cardiologists caring for postpartum patients should be aware of these potential lethal complications; prompt identification and administration of sublingual nitroglycerin can prevent severe complications of arrythmias, heart block, or cardiac arrest.

Impact of nitroglycerin on machine-learning fractional flow reserve in coronary computed tomography (CT)-angiography.

Nitroglycerin administration prior to examination improves stenosis assessment of coronary computed tomography (CT) angiography (CCTA). However, whether nitroglycerin influences CT-derived fractional flow reserve (FFR, CT-FFR) evaluation remains unclear. This study aimed to investigate the effect of nitroglycerin on diagnostic performance of CT-FFR. In this single-center retrospective study, 107 consecutive patients suspected of coronary artery disease (CAD) with nitroglycerin administration prior to CCTA in 2019 were matched to 107 patients without nitroglycerin in 2016 from Fuwai Hospital. All patients underwent CCTA and invasive FFR in a month. Vessel-based and patient-based accuracy and diagnostic performance of CT-FFR were compared between the two groups, as well as image quality, coronary artery diameter and evaluability. Quantitative variables were compared by Kruskal-Wallis H test. Categorical variables and rates were compared by χ2 test or Fisher exact test. A total of 214 patients (56.1±8.9 years, 155 male) with 237 target lesion vessels were analyzed, including 120 vessels in nitroglycerin and 117 vessels in non-nitroglycerin group. Per-vessel based accuracy of CT-FFR was higher in nitroglycerin group {80.0% [95% confidence interval (CI): 71.7-86.7%] vs. 68.4% (59.1-76.7%), P=0.041}. On a per-patient basis, nitroglycerin administration improved the accuracy [83.2% (74.7-89.7%) vs. 68.2% (58.5-76.9%), P=0.01], specificity [82.7% (69.7-91.8%) vs. 61.9% (48.8-73.9%), P=0.01], positive predictive value (PPV) [83.6% (73.6-90.4%) vs. 58.6% (50.0-66.9%), P=0.004], and area under the curve (AUC) [0.83 (0.75-0.89) vs. 0.71 (0.61-0.79), P=0.03] of CT-FFR. Vessel diameters (left main arteries: 4.3 vs. 3.8 mm, P<0.001; left anterior descending arteries: 3.1 vs. 2.9 mm, P=0.001; left circumflex arteries: 2.9 vs. 2.7 mm, P=0.01; right coronary arteries: 3.7 vs. 3.4 mm, P=0.001) and number of evaluable coronary arteries (11.0 vs. 8.0, P<0.001) were larger in nitroglycerin group. Nitroglycerin administration prior to CCTA has positive effects on diagnostic performance of CT-FFR.

Prostaglandin-E2 levels over the course of glyceryl trinitrate provoked migraine attacks

Administration of glyceryl trinitrate (GTN), a donor of nitric oxide, can induce migraine-like attacks in subjects with migraine. Provocation with GTN typically follows a biphasic pattern; it induces immediate headache in subjects with migraine, as well as in healthy controls, whereafter only subjects with migraine may develop a migraine-like headache several hours later. Interestingly, intravenous infusion with prostaglandin-E2 (PGE2) can also provoke a migraine-like headache, but seems to have a more rapid onset compared to GTN. The aim of the study was to shed light on the mechanistic aspect PGE2 has in migraine attack development. Therefore, PGE2 plasma levels were measured towards the (pre)ictal state of an attack, which we provoked with GTN. Blood samples from women with migraine (n = 37) and age-matched female controls (n = 25) were obtained before and ∼ 140 min and ∼ 320 min after GTN infusion. PGE2 levels were measured using liquid chromatography tandem mass spectrometry (LC-MS/MS) analysis. Data was analyzed using a generalized linear mixed-effect model. Immediate headache after GTN infusion occurred in 85 % of migraine participants and in 75 % of controls. A delayed onset migraine-like attack was observed in 82 % of migraine subjects and in none of the controls. PGE2 levels were not different between the interictal and preictal state (P = 0.527) nor between interictal and ictal state (defined as having migraine-like headache) (P = 0.141). Hence, no evidence was found that a rise in PGE2 is an essential step in the initiation of GTN-induced migraine-like attacks.

The impact of nitroglycerine and volume on gastric tube microperfusion assessed by indocyanine green fluorescence imaging

The influence of hypervolemia and intraoperative administration of nitroglycerine on gastric tube microperfusion remains unclear The present study aimed to investigate the impact of different hemodynamic settings on gastric tube microperfusion quantified by fluorescence imaging with Indocyanine green (ICG-FI) as a promising tool for perfusion evaluation. Three groups with seven pigs each were formed using noradrenaline, nitroglycerin, and hypervolemia for hemodynamic management, respectively. ICG-FI, hemodynamic parameters, and transit-time flow measurement (TTFM) in the right gastroepiploic artery were continuously assessed. Fluorescent microspheres (FM) were administered, and the partial pressure of tissue oxygen was quantified. The administration of nitroglycerine and hypervolemia were both associated with significantly impaired microperfusion compared to the noradrenaline group quantified by ICG-FI. Even the most minor differences in microperfusion could be sufficiently predicted which, however, could not be represented by the mean arterial pressure measurement. Histopathological findings supported these results with a higher degree of epithelial damage in areas with impaired perfusion. The values measured by ICG-FI significantly correlated with the FM measurement. Using tissue oxygenation and TTFM for perfusion measurement, changes in microperfusion could not be comprehended. Our results support current clinical practice with restrictive volume and catecholamine administration in major surgery. Hypervolemia and continuous administration of nitroglycerine should be avoided.

Experimental study of the effects of nitroglycerin, botulinum toxin A, and clopidogrel on bipedicled superficial inferior epigastric artery flap survival

Beneficial effects could be achieved by various agents such as nitroglycerin, botulinum toxin A (BoTA), and clopidogrel to improve skin flap ischaemia and venous congestion injuries. Eighty rats were subjected to either arterial ischaemia or venous congestion and applied to a bipedicled U-shaped superficial inferior epigastric artery (SIEA) flap with the administration of nitroglycerin, BoTA, or clopidogrel treatments. After 7 days, all rats were sacrificed for flap evaluation. Necrotic area percentage was significantly minimized in flaps treated with clopidogrel (24.49%) versus the ischemic flaps (34.78%); while nitroglycerin (19.22%) versus flaps with venous congestion (43.26%). With ischemia, light and electron microscopic assessments revealed that nitroglycerin produced degeneration of keratinocytes and disorganization of collagen fibers. At the same time, with clopidogrel administration, there was an improvement in the integrity of these structures. With venous congestion, nitroglycerin and BoTA treatments mitigated the epidermal and dermal injury; and clopidogrel caused coagulative necrosis. There was a significant increase in tissue gene expression and serum levels of vascular endothelial growth factor (VEGF) in ischemic flaps with BoTA and clopidogrel, nitroglycerin, and BoTA clopidogrel in flaps with venous congestion. With the 3 treatment agents, gene expression levels of tumor necrosis factor-α (TNF-α) were up-regulated in the flaps with ischemia and venous congestion. With all treatment modalities, its serum levels were significantly increased in flaps with venous congestion and significantly decreased in ischemic flaps. Our analyses suggest that the best treatment option for ischemic flaps is clopidogrel, while for flaps with venous congestion are nitroglycerin and BoTA.

Effective Following: A Counterpart to Leadership

Effective Following: A Counterpart to Leadership

Abstract 12018: Coronary Microvascular Dilatory Dysfunction According to the Types of Coronary Functional Abnormalitiescoronarymicrovascular Dilatory Dysfunction According to the Types of Coronary Functional Abnormalities

Introduction: Recently, there has been an increasing interest in coronary functional abnormalities (CFA), which include epicardial coronary spasm (ECS), microvascular spasm (MVS) and microvascular vasodilatory dysfunction (MVD). However, the frequency of MVD according to the types of CFA remains unclear. Hypothesis: Thus, this study aimed to investigate the frequency of MVD according to the types of CFA in patients with ischemia with non-obstructive coronary arteries (INOCA). Methods: This study included 63 patients with INOCA who underwent coronary angiography (CAG) and coronary function tests (CFT) to evaluate chest pain. In CFT, acetylcholine was first administered intracoronarily in a stepwise manner, followed by chest symptoms, electrocardiographic ST-T changes and CAG. ECS was defined as coronary vasoconstriction of &gt;90% on CAG accompanied by chest symptoms or electrocardiographic ST-T changes. Additionally, a focal spasm was defined as a transient vessel narrowing of &gt;90% within the borders of one isolated coronary segment (as defined by the American Heart Association), and a diffuse spasm was defined as a 90% diffuse vasoconstriction in ≥2 adjacent coronary segments of the coronary artery. Moreover, MVS was defined as the presence of both chest symptoms and ST-T changes with non-significant coronary vasoconstriction (&lt;90%) on CAG. After nitroglycerin administration, coronary flow reserve (CFR) and the index of microcirculatory resistance (IMR) were subsequently obtained by transvenous adenosine triphosphate infusion using a pressure wire. MVD was defined as CFR of &lt;2.0 or IMR of ≥25 units. Results: CAG and CFT were performed on 91 coronary arteries in 63 patients with INOCA, the results of which are shown below. Conclusions: These findings suggest that the frequency of MVD differs according to the types of CFA. Properly evaluating the MVD and reflecting this in the therapeutic strategy in patients with INOCA is desirable in clinical settings.

Abstract 12029: The Impact of the Myocardial Bridge on Coronary Functional Test in Patients With Ischemia With Non-Obstructive Coronary Arteries

Introduction: The possibility of myocardial bridge (MB) causing chest pain has been widely reported; however, the effect of MBs on coronary microvessels has not been thoroughly investigated. Hypothesis: Thus, this study evaluated the effects of MB on epicardial coronary artery and coronary microvascular function during coronary angiography (CAG) and coronary function tests (CFT) in patients with ischemia with non-obstructive coronary arteries (INOCA). Methods: This study included 57 patients with INOCA who underwent CAG and CFT to evaluate chest pain. In CFT, acetylcholine was first administered intracoronarily in a stepwise manner, followed by chest symptoms, electrocardiographic changes [Editor1] and CAG. Positive coronary spasm was defined as coronary vasoconstriction of &gt;90% on CAG accompanied by chest symptoms or electrocardiographic ST-T changes. After nitroglycerin administration, CAG was performed to assess MB, which is defined as the systolic narrowing of the coronary artery diameter by &gt;20% compared to that in diastole. Coronary flow reserve (CFR) and index of microcirculatory resistance (IMR) were subsequently obtained by transvenous adenosine triphosphate infusion using a pressure wire. Coronary microvascular vasodilatory dysfunction (CMD) was defined as CFR of &lt;2.0 or IMR of ≥25 units. Results: Of the 57 patients, 13 (23%) had MB. The CAG and coronary CFT results in the MB (+) and MB (–) groups are shown below. Conclusions: These findings suggest that MB predisposes to coronary spasms in patients with INOCA. Conversely, MBs may have a limited effect on microvessels, particularly in such patients.

Abstract 11578: A Case of Spontaneous Coronary Artery Dissection Masking as Acute Myopericarditis

Introduction: Chest pain is a common reason for emergency room visits. Acute coronary syndrome (ACS) remains a high mortality etiology of chest pain. Spontaneous coronary artery dissection (SCAD) is a rare cause of ACS in the general population, but a relatively common cause of ACS in young women. Case: Patient is a 29-year-old female with history of anxiety and fibroids that presented with chest pain. She described the chest pain as sharp, substernal, non-radiating that lasted for 10 minutes after eating dinner. The pain improved with leaning forward and resolved when lying on her stomach. She had a second episode of chest pain after 2 hours with similar characteristics which lasted 10 minutes. She was 4 months post-partum. She reported having a sore throat 4 days prior to the presentation. Troponin peaked at 0.173. ECG showed diffuse ST-elevation and PR depression in V3-V6 I II III aVF. TTE showed LVEF 65% and no wall motion abnormalities. CTA coronary showed 50-60% narrowing of mid LAD. Cardiac MR showed mild hypokinesis of mid-anteroseptal wall with associated subendocardial to midmyocardial delayed enhancement with focal elevations in myocardial native T1 and T2, and LVEF 53%. Coronary catheterization showed 50-60% stenosis in the mid-LAD distal to the first diagonal artery, there was no improvement in the stenosis after administration of intra-coronary nitroglycerin, there were no septals noted to arise from this area, consistent with diagnosis of SCAD (figure 1). Diagnosis: On initial evaluation, the etiology of her chest pain appeared to be myopericarditis. However, using CTA coronary, cardiac MR and coronary catheterization findings, the pain was more consistent with type 1 NSTEMI in the setting of SCAD. Patient was started on IV heparin, metoprolol tartrate, and aspirin. Conclusions: SCAD is a life-threating and often missed etiology of ACS. It requires a high index of suspicion and should be in the differential diagnosis in young women presenting with chest pain.

Abstract 15619: Smoking Towards Prinzmetal

Background: Vasospastic (Prinzmetal) angina is a result of coronary vasospasm leading to myocardial ischemia. It is defined by nitrate responsive angina, transient ischemic ECG changes, and coronary vasospasm. In this report, we highlight coronary angiographic findings of Prinzmetal angina and underscore tobacco use as a known risk factor. Case Presentation: A 62-year-old male with hypertension and tobacco use presented with acute substernal chest pain. Laboratory testing revealed elevated troponin to 17.4 mg/mL and ECG with new T-wave inversions in the lateral leads. Coronary angiogram revealed non-obstructive coronary artery disease (CAD) (Figure 1). He was discharged on medical therapy and instructed to stop smoking. Four days later, he returned with one day of chest pain that improved with sublingual nitroglycerin. Repeat troponin was elevated to 46.9 ng/mL and ECG revealed ST depressions in V2-V6. Repeat coronary angiogram revealed 99% narrowing in the proximal left circumflex (LCx) (Figure 2). Intra-arterial nitroglycerin administration led to resolution of the LCx narrowing (Figure 3). Conclusion: Prinzmetal angina can be precipitated by tobacco use. Clinicians ought to maintain a high degree of suspicion for Prinzmetal angina as an etiology of cardiac ischemia in patients who have non-obstructive CAD and concomitant tobacco use.

Abstract 10281: Meta-Analysis of Nitroglycerin’s Efficacy in Preventing the Incidence of Radial Artery Spasm and Occlusion During Trans-Radial Catheterization

Introduction. Trans-radial artery (TRA) becomes the most common entry route for cardiac catheterization. However, it may cause radial artery spasm (RAS) and subsequent radial artery occlusion (RAO). We conducted a meta-analysis of randomized controlled trials (RCTs) to assess the efficacy of different administration routes of nitroglycerin in reducing RAS and RAO compared to placebo in adult patients undergoing TRA cardiac catheterization. Methods. We searched Google Scholar, Web of Science, SCOPUS, EMBASE, PubMed (MEDLINE), and CENTRAL for RCTs up to April 23, 2022. The outcomes of interest were the incidence of RAS or RAO. Pooled risk ratio (RR) with the corresponding 95% confidence interval (CI) in a fixed-effects model was generated using RevMan Software (Version 5.4). We evaluated heterogeneity using I-square and Chi-square tests. Results. Eleven trials with 5,814 patients were included. Compared to placebo, the overall results showed that nitroglycerin was effective in preventing RAS (RR: 0.71 with 95% CI [0.59, 0.84], p= 0.0001), and RAO (RR: 0.74 with 95% CI [0.58, 0.94], p= 0.02). However, subgroup analysis according to the route of administration showed statistically significant result with subcutaneous nitroglycerin in prevention both RAS (RR: 0.57 with 95% CI [0.43, 0.77], p= 0.0003) and RAO (RR: 0.39 with 95% CI [0.16, 0.98, p= 0.05) but not intra-arterial nitroglycerine for RAS ((RR: 0.8 with 95% CI [0.63, 1.02], p= 0.07) and RAO (RR: 0.78 with 95% CI [0.6, 1.01], p= 0.06)), neither topical nitroglycerine for RAS ((RR: 0.73 with 95% CI [0.42, 1.24], p= 0.24). Conclusion. Our meta-analysis showed that subcutaneous nitroglycerin administration for TRA catheterization may prevent RAS and subsequent RAO compared to placebo. In contrast, intra-atrial and topical nitroglycerin have non-significant outcomes. Figure 1: Forest plot of the primary outcomes sub-grouped by route of administration (A- RAS, B- RAO). I2: I-squared; CI: confidence interval.

The efficacy of nitroglycerin to prevent radial artery spasm and occlusion during and after transradial catheterization: A systematic review and meta-analysis of randomized controlled trials.

Radial artery spasm (RAS) is the most common cause of transradial access site crossover and is a common intra-procedural complication. RAS incidence can lead to radial artery occlusion (RAO) postprocedure, preventing the radial artery as a future access site. We evaluated the efficacy of nitroglycerin preventing RAS and RAO during transradial catheterization discussing the different routes of administration, including topical, subcutaneous, and intra-arterial. A systematic review and meta-analysis included all relevant articles until April 23, 2022. We searched six databases Google Scholar, Web of Science, SCOPUS, EMBASE, PubMed (MEDLINE), and CENTRAL. We registered our review protocol in PROSPERO with ID: CRD42022330356. We included 11 trials with 5814 patients. Compared to placebo, the pooled analysis favored subcutaneous nitroglycerin in preventing RAS (risk ratio [RR]: 0.57 with 95% confidence interval [CI] [0.43-0.77], p = .0003) and RAO (RR: 0.39 with 95% CI [0.16-0.98], p = .05). In contrast to the intra-arterial nitroglycerin that showed nonstatistically significant results in preventing RAS and RAO (RR: 0.8 with 95% CI [0.63-1.02], p = .07)- (RR: 0.78 with 95% CI [0.6-1.01], p = .06)), respectively. Also, topical nitroglycerin did not prevent RAS (RR: 0.73 with 95% CI [0.42-1.24], p = .24). Compared with placebo, subcutaneous nitroglycerin during transradial catheterization reduced the incidence of RAS and RAO. Meanwhile, Intra-arterial and topical nitroglycerin did not show statistically significant outcomes. Subcutaneous nitroglycerin may be a practical and cost-effective technique to facilitate transradial catheterization; however, more RCTs are needed to evaluate the subcutaneous versus intra-arterial nitroglycerin administration.

The effects of ALDH2 Glu487Lys polymorphism on vasovagal syncope patients undergoing head-up tilt test supplemented with sublingual nitroglycerin

Background and objectiveHead-up tilt test (HUTT) is clinically advantageous for diagnosing patients with vasovagal syncope (VVS). Nitroglycerin is mainly used as a stimulant during HUTT, and mitochondrial aldehyde dehydrogenase 2 (ALDH2) is involved in the metabolism of nitroglycerin (NTG). ALDH2 Glu487Lys polymorphism (ALDH2 rs671) is the most common variant in the East Asian population. This study aimed to assess the effects of ALDH2 rs671 on VVS patients undergoing HUTT supplemented with sublingual NTG (HUTT-NTG). MethodsPatients with recurrent VVS (at least 2 times) who were admitted to the syncope center of our hospital were enrolled. All VVS patients have undergone HUTT. The polymorphism of Glu487Lys gene of ALDH2 was measured by the DNA Microarray Chip Method. The results of HUTT-NTG of VVS patients with different ALDH2 genotypes were compared and their hemodynamic characteristics were assessed.ResultsA total of 199 VVS patients were enrolled, including 101 patients in the ALDH2*1/*1 group and 98 patients in the ALDH2*2 group. Among patients undergoing HUTT-NTG, 70.3% of patients in the ALDH2*1/*1 group and 68.4% of patients in the ALDH2*2 group were positive, and the difference between the two groups was not statistically significant (P = 0.77). The proportions of VASIS I, VASIS II, and VASIS III were 40.6%, 8.9%, and 20.8% in the ALDH2*1/*1 group, respectively, and the corresponding proportions in the ALDH2*2 group were 36.7%, 11.2%, and 20.4%, respectively. There was no statistically significant difference between the two groups (P = 0.91). The hemodynamic characteristics of different genotypes in VVS patients undergoing HUTT-NTG were compared, and no statistically significant difference was found. The median time of syncopal episode occurred after NTG administration in the ALDH2*1/*1 group was 6 min (interquartile range [IQR]: 5.0–9.0), and it was 6.0 min in the ALDH2*2 group (IQR: 4.25–8.0, P = 0.64).ConclusionALDH2 Glu487Lys polymorphism did not affect the outcome of VVS patients undergoing HUTT-NTG, and no significant change in the hemodynamic characteristics of different genotypes was found.