Akinori Takizawa

Circadian variation of exercise capacity in patients with Prinzmetal's variant angina: role of exercise-induced coronary arterial spasm.

Thirteen patients with Prinzmetals variant angina performed treadmill exercise tests in the early morning in the afternoon of the same day. The attacks with ST elevation were induced repeatedly in all 13 patients in the early morning, but in only two patients in the afternoon. Propranolol did not suppress the exercise-induced attacks in all 13 patients. Diltiazem suppressed the attacks in all 13 patients phentolamine in eight of the nine patients. Coronary arteriograms demonstrated that spasm occluding completely or almost completely the large coronary artery supplying the area of myocardium showing ST elevation appeared during the attacks disappeared along with the attacks after nitroglycerin administration in all four patients in whom the attacks were induced by arm exercise in the catheterization laboratory. We conclude that there is circadian variation of exercise capacity in patients with Prinzmetals variant angina caused by coronary arterial spasm induced by exercise in the early morning but not in the afternoon.

Coronary arterial spasm and Prinzmetal's variant form of angina induced by hyperventilation and Tris-buffer infusion.

SUMMARY Vigorous hyperventilation was induced for five minutes immediately after a five-minute infusion of 100 ml of Tris-buffer (pH 10) in nine patients with Prinzmetals variant angina. In eight of the patients, chest pain with ischemic changes in the electrocardiogram occurred during this procedure or within five minutes after it ended. Coronary arterial spasm appeared after the procedure and disappeared after the administration of nitroglycerin in all four patients in whom coronary cinearteriography was performed. This was evident both before and after the procedure and after sublingual administration of nitroglycerin (0.6 mg). The oral administration of 90 mg of diltiazem, a calcium antagonistic drug, two hours before, completely suppressed the attack induced by the procedure in all of the five patients who received this drug. We conclude that hyperventilation plus Tris-buffer infusion induces coronary arterial spasm and anginal attack in patients with Prinzmetals variant angina and that diltiazem suppresses these reactions.

Exertional angina pectoris caused by coronary arterial spasm: Effects of various drugs

In four patients with exertional angina induced by arm exercise, coronary arteriograms taken before, during and after the attack demonstrated that spasm appeared in the large coronary artery supplying the area of myocardium shown to be ischemic in the electrocardiogram during the attack. The spasm disappeared with subsidence of the attack after administration of nitroglycerin. Anginal attacks induced by treadmill exercise were not suppressed by propranolol, 60 mg orally, in two of the four patients. However, such attacks were suppressed in all patients by oral administration of diltiazem (90 mg, four patients) or nifedipine (20 mg, three patients) or intramuscular injection of phentolamine (0.2 mg/kg body weight, three patients). It is concluded that coronary arterial spasm can be induced by exercise and can cause exertional angina in some patients. Diltiazem and nifedipine, calcium antagonistic drugs, prevent spasm.

Upfront thrombus aspiration in primary coronary intervention for patients with ST-segment elevation acute myocardial infarction: report of the VAMPIRE (VAcuuM asPIration thrombus REmoval) trial.

OBJECTIVES This study evaluated safety and efficacy of upfront thrombus aspiration during primary percutaneous coronary intervention (PCI) in patients with ST-segment elevation myocardial infarction (STEMI). BACKGROUND Distal embolization during primary PCI results in reduced myocardial perfusion and poor clinical outcomes. METHODS The VAMPIRE (VAcuuM asPIration thrombus REmoval) study was a prospective, randomized, controlled multicenter trial conducted in 23 institutions. Patients (N = 355) presenting within 24 h of STEMI symptoms onset were randomized to primary PCI with (n = 180) or without (n = 175) upfront thrombus aspiration using Nipros TransVascular Aspiration Catheter (Osaka, Japan). RESULTS The TransVascular Aspiration Catheter reached the lesion in 100% of cases. It successfully crossed the target obstruction in 86% without any delay in procedure time or time to reperfusion; whereas macroscopic thrombi were removed in 75% of the cases. Procedure success was similar between groups (98.9% vs. 98.3%). There was a trend toward lower incidence of slow or no reflow (primary end point-defined as a Thrombolysis In Myocardial Infarction flow grade <3) in patients treated with aspiration versus conventional primary PCI (12.4% vs. 19.4%, p = 0.07). Rate of myocardial blush grade 3 was higher in the aspiration group (46.0% vs. 20.5%, p < 0.001). Aspiration was most effective in patients presenting after 6 h of symptoms onset (slow flow rate: 8.1% vs. 37.6%, p = 0.01). CONCLUSIONS This study suggested the safety of primary PCI with upfront thrombectomy using a novel device in patients with STEMI. The study showed a trend toward improved myocardial perfusion and lower clinical events in patients treated with aspiration. Patients presenting late after STEMI appear to benefit the most from thrombectomy.

Tissue Factor Expression on Macrophages in Coronary Plaques in Patients with Unstable Angina

Tissue factor is a membrane-bound glycoprotein that functions in the extrinsic pathway of blood coagulation by acting as a cofactor for factor VII, and the resulting complex leads to thrombin production in vivo. The purpose of the present study is to determine whether macrophages express tissue factor in human coronary atherosclerotic plaques. We examined directional coronary atherectomy specimens from 24 patients with unstable angina and 23 with stable exertional angina. In these specimens, macrophages were detected in 22 (92%) of 24 patients with unstable angina versus 12 (52%) of 23 with stable exertional angina (P = .003). The percentage of macrophage infiltration area was significantly larger in patients with unstable angina than in those with stable exertional angina (17 +/- 3% versus 6 +/- 2%, P = .008). The immunohistochemical double staining revealed the expression of tissue factor on macrophages in 18 (75%) of 24 patients with unstable angina versus 3 (13%) of 23 with stable exertional angina (P < .0001). Thrombus was identified in 20 (83%) of 24 patients with unstable angina versus 12 (52%) of 23 with stable exertional angina (P = .02). Fibrin deposition was mainly observed around macrophages expressing tissue factor in the patients with unstable angina. We have shown that tissue factor expression on macrophages was more frequent in coronary atherosclerotic plaques in patients with unstable angina. Tissue factor expressed on macrophages may play an important role in the thrombogenicity in coronary atherosclerotic plaques of these patients.

Comparison of coronary arteriographic findings during angina pectoris associated with S-T elevation or depression.

Coronary arteriographic findings during an attack of angina pectoris associated with S-T segment elevation and angina associated with S-T depression were compared in 54 patients. Thirty-eight attacks with S-T segment elevation included 2 that were spontaneous, 6 induced by methacholine, 4 by epinephrine with or without propranolol, 9 by arm exercise, 5 by hyperventilation with or without Tris-buffer infusion and 12 by ergonovine maleate. Twenty-nine of the 38 attacks were associated with total occlusion, 8 with subtotal occlusion and 1 with diffuse narrowing of a major coronary artery caused by spasm. Twenty-six attacks with S-T segment depression included 3 induced by methacholine, 13 by arm exercise, 3 by hyperventilation with or without Tris-buffer infusion and 7 by ergonovine maleate. Eight of the 26 attacks were associated with subtotal occlusion and 9 with diffuse narrowing of a major coronary artery caused by spasm; 3 attacks were associated with total occlusion of a major coronary artery well supplied with collateral vessels and 2 with total occlusion of a small coronary branch caused by spasm. Four attacks were associated not with spasm but with fixed subtotal occlusion of a major coronary artery (3 attacks) or total occlusion of a major coronary artery receiving collateral vessels (1 attack). Only 2 of the 31 patients with S-T segment elevation had collateral vessels compared with 8 of the 16 patients with S-T segment depression (p less than 0.001). It is concluded that angina pectoris associated with S-T segment elevation usually indicates more severe myocardial ischemia than angina associated with S-T segment depression.

Late Adverse Events After Implantation of Sirolimus-Eluting Stent and Bare-Metal Stent Long-Term (5–7 Years) Follow-Up of the Coronary Revascularization Demonstrating Outcome Study-Kyoto Registry Cohort-2

Background—Late adverse events such as very late stent thrombosis (VLST) or late target-lesion revascularization (TLR) after first-generation sirolimus-eluting stents (SES) implantation have not been yet fully characterized at long term in comparison with those after bare-metal stent (BMS) implantation. Methods and Results—Among 13 058 consecutive patients undergoing first percutaneous coronary intervention in the Coronary REvascularization Demonstrating Outcome study-Kyoto registry Cohort-2, 5078 patients were treated with SES only, and 5392 patients were treated with BMS only. During 7-year follow-up, VLST and late TLR beyond 1 year after SES implantation occurred constantly and without attenuation at 0.24% per year and at 2.0% per year, respectively. Cumulative 7-year incidence of VLST was significantly higher in the SES group than that in the BMS group (1.43% versus 0.68%, P<0.0001). However, there was no excess of all-cause death beyond 1 year in the SES group as compared with that in the BMS group (20.8% versus 19.6%, P=0.91). Cumulative incidences of late TLR (both overall and clinically driven) were also significantly higher in the SES group than in the BMS group (12.0% versus 4.1%, P<0.0001 and 8.5% versus 2.6%, P<0.0001, respectively), leading to late catch-up of the SES group to the BMS group regarding TLR through the entire 7-year follow-up (18.8% versus 25.2%, and 10.6% versus 10.2%, respectively). Clinical presentation as acute coronary syndrome was more common at the time of late SES TLR compared with early SES TLR (21.2% and 10.0%). Conclusions—Late catch-up phenomenon regarding stent thrombosis and TLR was significantly more pronounced with SES than that with BMS. This limitation should remain the target for improvements of DES technology.

Variant angina induced by alcohol ingestion

We gave alcohol to 15 patients with variant angina to induce the attacks at the hospital. Anginal attacks were repeatedly induced in seven of them. Although the time lag between alcohol ingestion and the attacks varied widely among patients, from 1.5 to 12 hours, it was fairly constant in each patient. We carefully examined the histories of 101 patients with variant angina to become familiar with the relationship between alcohol ingestion and the attacks of angina. Seventy-one patients took alcohol in their daily lives. Nineteen of the 71 patients (26.8%) who took alcohol had a definite relationship between alcohol ingestion and the attacks. We conclude that alcohol induces anginal attacks or coronary artery spasm in not a small number of patients with variant angina.

Duration of Dual Antiplatelet Therapy and Long-Term Clinical Outcome After Coronary Drug-Eluting Stent Implantation Landmark Analyses From the CREDO-Kyoto PCI/CABG Registry Cohort-2

Background— Optimal duration of dual antiplatelet therapy (DAPT) after drug-eluting stent (DES) implantation has not been yet fully elucidated. Methods and Results— We assessed the influence of prolonged thienopyridine therapy on clinical outcomes with landmark analysis at 4 and 13 months after DES implantation. Among 6802 patients with at least 1 DES implantation in the CREDO-Kyoto Registry Cohort-2, 6309 patients (on thienopyridine, 5438 patients; off thienopyridine, 871 patients) and 5901 patients (on thienopyridine, 4098 patients; off thienopyridine, 1803 patients) were eligible for the 4- and 13-month landmark analyses, respectively. The majority of patients had stable coronary artery disease (73%) and received sirolimus-eluting stents (93%), and approximately 90% of thienopyridine was ticlopidine. Patients taking thienopyridine had more complex comorbidities and more complex lesion and procedural characteristics as compared with patients not taking thienopyridine. After adjusting for confounders, thienopyridine use was not associated with decreased risk for death/myocardial infarction/stroke (hazard ratio [HR], 1.13; 95% confidence interval [CI], 0.89–1.43, P=0.32 in the 4-month landmark analysis; HR, 1.14; 95% CI, 0.90–1.45, P=0.29 in the 13-month landmark analysis, respectively), whereas the risk for GUSTO moderate/severe bleeding tended to be higher in patients taking thienopyridine (HR, 1.51; 95% CI, 1.00–2.23, P=0.049 in the 4-month landmark analysis; HR, 1.44; 95% CI, 0.99–2.09, P=0.057 in the 13-month landmark analysis, respectively). Conclusions— Prolonged thienopyridine therapy beyond 4 and 13 months appeared not to be associated with reduction in ischemic events but to be associated with a trend toward increased bleeding. Optimal duration of DAPT after DES implantation might be shorter than the currently recommended 1-year interval.

Alkalosis-induced coronary vasoconstriction: Effects of calcium, diltiazem, nitroglycerin, and propranolol

We examined the effects of changes in pH, Ca2+ concentration, diltiazem, nitroglycerin, and propranolol on the vascular tone of the isolated rabbit coronary artery. Stepwise increase in pH of the bath fluid caused pH-dependent increased vascular tone. Increase in Ca2+ concentration of the bath fluid also resulted in increased vascular tone, while removal of Ca2+ abolished the high pH-induced elevated vascular tone. Diltiazem and nitroglycerin suppressed the high pH-induced increased vascular tone. Propranolol in high concentrations exhibited a direct inhibitory effect on the high pH-induced increased vascular tone. We conclude that high pH induces coronary vasoconstriction principally by increasing transmembrane influx of Ca2+ and that diltiazem and nitroglycerin suppress this action.