C69 EFFECTIVENESS AND SAFETY OF DISTINCT ANTIPLATELET REGIMENS AFTER TRANSCATHETER LEFT ATRIALE APPENDAGE OCCLUSION: A SINGLE CENTER REAL–WORLD EXPERIENCE

Transcatheter left atrial appendage occlusion (LAAO) has emerged as a reliable tool to prevent thromboembolic events, in particular ischemic stroke, in patients with atrial fibrillation (AF) in the absence of mitral stenosis/valve prosthesis and contraindication to oral anticoagulation (OAC). Antiplatelet therapy (APT) is required after device implantation to prevent device–related thrombus (DRT). Previous studies provided conflicting results on the optimal APT regimen after LAAO. Thus, herein we aimed at assessing the comparative effectiveness and safety of distinct APT regimens. We conducted a real–world single–center observational study including consecutive AF patients that underwent LAAO at the University Hospital of Parma between October 2010 and June 2021. Clinical follow–up included all successfully implanted patients. Primary endpoint was net efficacy outcome, a composite of any ischemic or hemorrhagic event. Secondary endpoints were ischemic (any of the following: ischemic stroke, transient ischemic attack [TIA], DRT, systemic embolism) and hemorrhagic (major [≥3] bleedings according to Bleeding Academic Research Consortium [BARC] classification) complications alone. We enrolled a total of 130 patients (median age 77.0 [72.7;81.0] years; 78 [60.0%] men). History of hemorrhagic stroke in OAC (74 [56.9%]) was the main indication for LAAO. Technical procedure success was achieved in 123 (94.6%) patients. According to multidisciplinary team evaluation, immediately after LAAO, 39 (31.7%) patients received short (≤ 1 month)–dual APT (DAPT) consisting of cardioaspirin and clopidogrel, 35 (28.5%) long (>1, ≤12 months)–DAPT and 49 (39.8%) single APT (SAPT). At a median follow–up of 32 months, the incidence of primary endpoint was significantly lower in short–DAPT group (3 [7.7%] vs. 7 [20.0%] in long–DAPT vs. 14 [28.6%] in SAPT, p = 0.049], mainly driven by a lower occurrence of bleeding endpoint (0 [0.0] vs. 4 [11.4%] in long–DAPT vs. 9 [18.4%] in SAPT, p = 0.020) without differences in the incidence of ischemic endpoint (p = 0.916). Finally, comparison of the Kaplan–Meier curves showed that short–DAPT group had a higher primary endpoint–free survival (p = 0.015) compared to the others. In summary, our study highlighted that short (≤ 1 month)–DAPT regimen after LAAO is associated with better outcomes, mainly driven by reduction of major bleedings. Strong evidences arising from randomized trials are warranted to support these findings.

P56 SPONTANEOUS CORONARY ARTERY DISSECTIONS: ANALYSIS OF NON TRADITIONAL RISK FACTORS

 

The etiology of spontaneous coronary dissection (SCAD) is not well defined and Non traditional risk factors (NT–RF) have assumed increasing interest, but few data are available. NT–RF include three categories: Sex–related (SR–NT–FR), Sex–predominant (SP–NT–RF) and Gender–related (GR–NT–RF). (Table 1)

Aim of the Study

The objective of our analysis was to evaluate the incidence of NT–RF in Parma SCAD registry population.

Material and methods

We reviewed 62 patients with SCAD enrolled between January 2013 through November 2021

Results

Traditional risk factors were less common: hypertension was the most prevalent (39 pts, 62.9%). When considering NT–RF, 51 patients (82%) had at least one of all, with at least one SR–RF (66%) or GR–RF (64,5%). Patients with NT–RF were younger at time of SCAD (mean age 53 vs 66; p = 0.027) and they were predominantly females (48 vs 7 pts, p = 0.004) (Table 2). No differences were found among NT–RF SCAD and nNT–RF SCAD patients by fibromuscular dysplasia, peripheral arterial disease and chronic kidney disease. Patients with SCAD more often presented with non ST–segment elevation myocardial infarction (43 pts, 72.6%) vs ST–segment elevation (17 pts, 27.4%). No differences in clinical presentation and angiographic characteristics were found among NT–RF and nNT–RF patients group. MACE occurred in 17.7% of patients of the overall study population, at a median follow–up of 23 (interquartile range: 11;57) months. When comparing the incidence of cardiovascular events in the 2 study groups there was a trend toward a higher prevalence of MACE in NT–RF group without statistical significance (NT–RF SCAD 19.6% – nNT–RF SCAD 9.1%; p = 0.4). (Table 3)

Conclusion

SCAD is an emerging cause of myocardial infarction in young and middle–aged women without the traditional cardiovascular risk profile. Although overall survival seems good, SCAD is a potentially malignant disease which can present with ventricular arrhythmias and sudden cardiac death. Risk estimation is difficult in women, due to the scarce validity of prediction models, therefore a great effort must be made by the clinical community for the widespread diffusion and use of models incorporating NT–RF. Acknowledgement of peculiar features of this disease could help clinicians and researchers to establish targeted interventions for cardiovascular primary prevention, early diagnosis and secondary prevention in women, including rehabilitation and stress management programmes.

Doppler tissue echocardiography: myocardial wall motion velocities in essential hypertension

AIMS

Doppler tissue echocardiography (DTE) was applied to extract the myocardial wall velocities along different planes and evaluate the left ventricular function in essential hypertension.

METHODS AND RESULTS

Fifty-four hypertensives (HT) were compared to a control group of 31 normotensive (NT) subjects. The short-axis shortening and lengthening was assessed through the parasternal projections, sampling from interventricular septum and posterior wall. Through the apical projections the mitral annulus excursion was observed at four sites (anterior, posteroseptal, lateral, inferior walls) to assess the longitudinal dynamic of the heart. In each myocardial segment, peak velocity and time-velocity integral for systolic (S) and diastolic waves (E and A) were measured and their means for the long- and short-axis directions were calculated. Significant changes in hypertensives involved mainly the longitudinal motion. In diastole, the E-wave relaxation velocity was significantly decreased and the late A-wave velocity was unchanged. The E/A velocity ratio was significantly reduced. Relaxation velocity was negatively correlated to age, left ventricular mass and diastolic blood pressure. In systole, the peak S-wave shortening velocity was reduced and no association with age, left ventricular mass and blood pressure could be demonstrated. The range of segmental data produced by DTE proved useful to manufacture sensitive indices for recognition of hypertensive damage. Single DTE variables also proved slightly more sensitive than those extracted from the mitral flow pattern for the discrimination of HT patients.

CONCLUSION

The presence of impaired relaxation was confirmed by DTE in a large portion of patients with hypertension and left ventricular hypertrophy. A peculiar systolic disturbance is evidenced by this technique. DTE-derived information can be used to detect early and quantify target-organ damage and its progression or regression during antihypertensive treatment.

Estrogen derivative relaxes rabbit aorta via the endothelial receptor system

BACKGROUND

It is well known that sexual hormones, in particular estrogens, may influence the cardiovascular system. Experimental and clinical studies have shown that estrogen directly or indirectly modulates the reactivity of vascular smooth muscle but at present the mechanism of action of this hormone has yet to be clarified. The aim of this study was to evaluate the vascular effects of a synthetic non-steroid estrogen, diethylstilbestrol, and the possible involvement of endothelial function.

METHODS

We investigated, on aortic strips of a female rabbit, the inhibitory effects of diethylstilbestrol on the contractions induced by different spasmogenic agents, noradrenaline (10(-6) M), angiotensin II (10(-6) M), serotonin (10(-6) M), and KCl (10(-1) M). Some experiments were performed in high K+, Ca++-free solution. In some experiments endothelial function was abolished by mechanical ablation. Another series of experiments was incubated (30 min) with N(G)-monomethyl-L-arginine, which inhibits nitric oxide synthase or with tamoxifen, a specific antagonist of estrogen receptors.

RESULTS

At doses from 10(-6) M to 10(-4) M, diethylstilbestrol showed an evident spasmolytic action on contractions induced by noradrenaline, angiotensin II and serotonin but no significant effect was observed on KCl spasm. The inhibitory response of diethylstilbestrol to increased vascular tone induced by noradrenaline disappeared when the endothelial function, validated by the acetylcholine test, was abolished by mechanical ablation. When tested in high K+, Ca++-free solution, diethylstilbestrol did not significantly shift the cumulative dose-response curve of calcium. In the experiments performed with N(G)-monomethyl-L-arginine, diethylstilbestrol failed to induce vasodilation suggesting that its action may be related to synthesis of nitric oxide. Moreover, in the presence of tamoxifen, diethylstilbestrol was unable to induce vasodilation.

CONCLUSIONS

The early occurrence of vasodilation is in favor of a direct effect and seems to exclude a regulation of gene expression. These results suggest that estrogens may directly regulate vascular tone interacting with its specific endothelial cell receptors through the release of nitric oxide.

Long-term changes in left ventricular mass, chamber size and function after valve replacement in patients with severe aortic stenosis and depressed ejection fraction

We studied 21 patients undergoing valve replacement for severe aortic stenosis and marked left ventricular dysfunction (mean ejection fraction 27 +/- 7.9%) without significant coronary disease or other valve diseases. At 5-60 months (average 26 +/- 18) after surgery, the patients underwent a clinical history, physical examination and a complete M-mode, two-dimensional and Doppler transthoracic echocardiographic study. Thirteen patients were examined with cardiopulmonary exercise testing. Two patients with a low preoperative transvalvular pressure gradient (<50 mm Hg) died postoperatively. Nineteen patients were tested at follow-up. All patients showed an improvement in functional class, an increase in ejection fraction (EF), a normalization in left ventricular diameters, volumes and stress indices and a reduction in left ventricular mass which correlated with EF increase. Cardiopulmonary exercise testing showed a good exercise capacity. In conclusion, in patients affected by severe aortic stenosis and marked preoperative left ventricular dysfunction valve replacement induces a favorable remodeling of the left ventricle, as shown by a late postoperative examination. The regression of hypertrophy is a positive event which correlates with the improvement in EF.

[Mild hypercholesterolemia. Diagnosis and prognosis]

The finding of normocholesterolaemia, characterized by plasmatic values of total cholesterol < 2 g/l, which may hide silent lipidic alterations, is not by itself sufficient to rule out the existence of cardiovascular risk. First level screening of patients exposed to atherogenic risk must begin from dosage of three basic lipidic indicators, represented by total cholesterol, triglycerides, and HDL cholesterol. By using the values of the three above-mentioned indicators and by applying Friedewald's formula, it is possible to calculate LDL cholesterol indirectly. Atherogenic risk is present when HDL cholesterol and LDL cholesterol show plasmatic concentration inferior to 0.35 g/l and superior to 1,3 g/l respectively. The European Atherosclerosis Society lists five hyperlipidaemic classes, from A to E, determined on the basis of plasmatic levels of cholesterol and triglycerides. Mild hypercolesterolaemia associated with modest atherogenic risk and which largely occurs in people and is frequently underestimated form a diagnostic point of view, contributes to cardiovascular mortality more considerably than more serious forms of hypercholesterolaemia. On the basis of this observation, there originated the programmatic proposal for the prevention of hyperlipidaemic complications, presented by the Authors.

Mechanism of action of human calcitonin gene-related peptide in rabbit heart and in human mammary arteries

We investigated the effects of human calcitonin gene-related peptide (CGRP) on isolated rabbit hearts to evaluate the mechanisms responsible for the vasodilatory action of the peptide on the coronary district, monitoring contemporaneously the effects on left ventricular pressure (LVP) and heart rate (HR). We also evaluated the reactivity of the human internal mammary artery (IMA) to excitatory drugs acting with different mechanisms and the inhibitory response to CGRP in comparison with the commonly used vasodilatory agents. The peptide induced a slight inhibitory effect on the basal coronary perfusion pressure (CPP), whereas it was ineffective on the inotropism and chronotropism. A more detectable coronary vasodilation was evident when CPP was increased by spasmogenic agents [vasopressin, methoxamine, Bay K 8644, and prostaglandin F2 alpha (PGF2 alpha)]. This inhibitory effect was dose dependent (10(-11)-10(-8) M) and apparently not specific, occurring to the same extent on different stimuli. Forskolin (10(-8) M), an adenylate-cyclase activator, and indomethacin (1.4 x 10(-5) M), a cyclooxygenase inhibitor, did not modify the spasmolytic activity of CGRP on precontracted coronary smooth muscle. The experiments performed on the segments of IMA, used for myocardial revascularization of patients affected by coronary diseases, have shown an evident spasmolytic action of CGRP on increased vascular tone induced by KCl (90 mM), noradrenaline (10(-5) M), serotonin (10(-6) M), and angiotensin II (10(-6) M). These inhibitory responses of CGRP on the spasmogenic compounds disappeared when the endothelial function of IMA, validated by the acetylcholine test, was abolished by mechanical ablation. A series of IMA segments was incubated (30 min) with N(G)-monomethil-L-arginine (L-NMMA), which inhibits nitric oxide (NO) synthase. In these experiments, the peptide failed to induce the vasodilation, suggesting that its action may be related to synthesis of NO. All these results show that CGRP is able to induce a potent vasodilatory action on different vessels of humans (internal mammary artery) and animals (rabbit coronary arteries). In particular the data obtained from IMA demonstrated that the vasorelaxant effect was related to synthesis of NO, one of the most studied endothelium-derived relaxing factors (EDRFs).

[The short- and long-term results in heart surgery of the elderly]

We have studied retrospectively 106 patients aged 69 years or older (range 69 to 79) who underwent cardiac surgery between November 1986 and December 1989. The majority of patients (61%) were male. Coronary artery bypass surgery was performed in 59 patients, isolated valve replacement in 38 and combined valve replacement with coronary artery bypass surgery in 5. Two patients underwent ascending aorta replacement for aortic dissection and 2 ventricular aneurysmectomy and postinfarction ventricular septal defect repair. The mean postoperative hospital stay was 12 days. Ninety-one percent of patients underwent a primary elective operation and 9% required an emergency operation. Hospital mortality was 5% (n = 6). All hospital survivors were followed up by telephone contact (mean follow-up: 37 months) to determine presence or absence of chest pain, dyspnea, postoperative NYHA class and the overall effect of surgery on quality of life. There were 16 follow-up deaths; 5 were non cardiac. Follow-up study showed significant improvement in symptom status and quality of life (96%). We concluded that cardiac surgery in the elderly, although associated with increased operative risk, gives excellent relief of symptoms and good survival.

[Effects of amrinone on isolated heart preparations: comparative study with other inotropic agents]

We compared the effects of the phosphodiesterase inhibitor amrinone, the beta-adrenergic partial agonist xamoterol and the digitalis glycoside, ouabain, on isolated rabbit hearts perfused with the Langendorff technique. Heart rate, left ventricular pressure, as an index of myocardial contractility and coronary perfusion pressure, as an index of coronary resistances, were assessed before and after each drug. Perfusion with concentrations of each agent varying from 10(-9) to 10(-4) M induced a dose-dependent increase of left ventricular systolic pressure averaging 32.5 +/- 1.5% after amrinone (10(-5) M), 46.2 +/- 0.5% after xamoterol (10(-5) M) and 19.0 +/- 2.1% after ouabain (10(-4) M). Among the 3 agents, only amrinone was able to reduce basal coronary perfusion pressure (18.4 +/- 1.2% at the dose of 10(-5) M) and inhibit vasopressin-induced coronary spasm (86.8 +/- 2.5% inhibition at 10(-5) M); no significant change of coronary perfusion pressure was noted with either xamoterol or ouabain. Heart rate was not significantly modified by amrinone whereas, at the doses of 10(-5)-10(-4) M, xamoterol increased it by 21.6 +/- 0.7% and ouabain reduced it by 12.3 +/- 1.1%. Our results show that amrinone, in comparison with digitalis glycosides and beta-adrenergic agonists, presents the unique property to increase myocardial contractility with concomitant coronary vasodilation without significant changes of heart rate. Ouabain has a less potent positive inotropic activity and a slight negative chronotropic action, whereas xamoterol inotropic effect is accompanied by an increase of heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Different effects of captopril and other angiotensin converting enzyme inhibitors on cardiovascular preparations

The effects of captopril and of other angiotensin-converting enzyme inhibitors (zofenopril, fosenopril and enalaprilic acid) were tested on the isolated rabbit heart and aorta. Captopril elicited an erratic negative inotropic effect and a reduction in basal coronary perfusion pressure (10(-5)-10(-4) M). The increase of coronary perfusion pressure induced by vasopressin, methoxamine, angiotensin II and Bay K 8644 was partially antagonized by captopril (10(-7)-10(-4) M) in a non-specific manner. These actions were not modified by saralasin or indomethacin and by ex vivo pretreatment with captopril itself. On the aortic strips, the contraction plateau induced by KCl and angiotensin II was partially inhibited (10(-6)-10(-4) M), while no effect was observed on those induced by noradrenaline, serotonin and PGF2 alpha. The Ca2+ concentration-response curve appeared shifted to the right in a non-competitive manner. The other angiotensin-converting enzyme inhibitors showed no effect up to 10(-4) M on isolated heart or aorta. Results obtained with captopril were consistent with vasorelaxant activity independent of the tissue renin-angiotensin system. Modulatory activity on the intracellular calcium movement may be involved.

[The adrenergic beta system in an experimental model of heart failure]

Reports in the literature have suggested that a complex alteration in beta-receptor pathway takes place in failing human myocardium. The purpose of our study was to evaluate the beta-adrenergic receptor system in an experimental model of heart failure induced by monocrotaline in rats. Monocrotaline, administered with a single intraperitoneal injection (50 mg/Kg), causes pulmonary hypertension and right ventricular hypertrophy, associated with congestive heart failure. beta 1 and beta 2-receptors were characterized in the right ventricle by direct radioligand binding utilizing [125I] Iodocyanopindolol and selective beta 1-(CGP 20712A) and beta 2-(ICI 118551) antagonists. Adenylate cyclase was measured in basal condition and in the presence of different stimulators as isoproterenol with ICI 118551 (beta 1-receptor-stimulated activity), isoproterenol with CGP 20712A (beta 2-receptor-stimulated activity), Gpp(NH)p, NaF and forskolin. In the right ventricle of the failing hearts the beta 1-receptor density decreased selectively (-55.8%) while the beta 2-receptor density was unchanged. Modifications in the adenylate cyclase system were demonstrated: a reduction in the basal and beta 1- and beta 2-stimulated adenylate cyclase activity; a decrease in adenylate cyclase activation elicited by Gpp(NH)p, but not by forskolin and NaF. In conclusion, these data suggest that in monocrotaline-induced heart failure in the rat there is a selective beta 1-receptor down-regulation and an impaired coupling efficiency of G proteins. These results are in line with biochemical changes found in patients with heart failure.

[Pharmacologic characterization of the internal mammary artery used in myocardial revascularization]

The aim of this study concerned the pharmacological investigation of the isolated internal mammary artery. Spirally-cut vascular segments were obtained from patients undergoing myocardial revascularization and set up in isolated baths under isometrical tension. Reactivity of internal mammary artery preparations to stimulatory and inhibitory agents was evaluated. KCl (90 mM), noradrenaline (10-8)-10(-5) M) and serotonine (10(-9)-10(-5) M) induced a tonic contraction lasting for more than 60 min. Angiotensin II (10(-6)-10(-5) M) and dopamine (10)-8)-10(4) M) resulted virtually uneffective. The serotonine-induced contractions were strongly inhibited by ketanserin (10-9)-10(-6) M), a selective S2-blocker, and also by verapamil (10(-3)-10(-6) M) and nitroglycerin (10(-7)-10(-5) M). These data suggest that internal mammary artery is sensitive to different contractile agents, in particular serotonine activates muscular contractions through S2 receptors. The knowledge of such a mechanism may be of clinical relevance.

Inhibitory actions of amiodarone on the isolated rabbit heart and aorta

1. The inhibitory actions of amiodarone on the isolated rabbit heart and aorta have been studied. 2. Amiodarone inhibited vasopressin- and ergonovine-induced coronary spasm, starting from a concentration of 10(-7) M which did not affect myocardial contractility to 10(-4) M, which decreased myocardial contractility. 3. Sinus node activity was largely unaffected even when the highest dose of 10(-4) M was used. 4. Amiodarone did not modify the smooth muscle contraction in rabbit aorta strips precontracted with noradrenaline or potassium. 5. Comparison with other inhibitors of the cardiovascular system (alpha- and beta-blockers, nitrates, calcium entry blockers) points out a peculiar pharmacological profile of amiodarone and indicates some doubts about its presumed anti-adrenergic properties.

Action of steroid sex hormones on the isolated rabbit heart

Steroid sex hormones, testosterone, progesterone and diethylstilbestrol, have been tested on the isolated rabbit heart. These hormones produced a negative inotropic effect (1-10 mumol/l) and an inhibitory effect on the vasopressin- or ergonovine-induced coronary spasm (0.1-10 mumol/l). Basal coronary tone was increased by testosterone and progesterone, while diethylstilbestrol induced a slight reduction of coronary perfusion pressure. The negative inotropic effect was reversed by calcium and isoprenaline, thus resembling the calcium entry blocker activity. The activation of myocardial and coronary contractility by the calcium agonist, Bay K 8644, was antagonized by all these hormones. These observations demonstrated an influence of steroid sex hormones with calcium fluxes in the isolated rabbit heart.