Hitoshi Yasumoto

Antiplatelet Therapy and Stent Thrombosis After Sirolimus-Eluting Stent Implantation

Background— The influences of antiplatelet therapy discontinuation on the risk of stent thrombosis and long-term clinical outcomes after drug-eluting stent implantation have not yet been addressed adequately. Methods and Results— In an observational study in Japan, 2-year outcomes were assessed in 10 778 patients undergoing sirolimus-eluting stent implantation. Data on status of antiplatelet therapy during follow-up were collected prospectively. Incidences of definite stent thrombosis were 0.34% at 30 days, 0.54% at 1 year, and 0.77% at 2 years. Thienopyridine use was maintained in 97%, 62%, and 50% of patients at 30 days, 1 year, and 2 years, respectively. Patients who discontinued both thienopyridine and aspirin had a significantly higher rate of stent thrombosis than those who continued both in the intervals of 31 to 180 days, 181 to 365 days, and 366 to 548 days after stent implantation (1.76% versus 0.1%, P<0.001; 0.72% versus 0.07%, P=0.02; and 2.1% versus 0.14%, P=0.004, respectively). When discontinuation of aspirin was taken into account, patients who discontinued thienopyridine only did not have an excess of stent thrombosis in any of the time intervals studied. Adjusted rates of death or myocardial infarction at 24 months were 4.1% for patients taking thienopyridine and 4.1% for patients not taking thienopyridine (P=0.99) in the 6-month landmark analysis. Conclusions— Discontinuation of both thienopyridine and aspirin, but not discontinuation of thienopyridine therapy only, was associated with an increased risk of stent thrombosis. Landmark analysis did not suggest an apparent clinical benefit of thienopyridine use beyond 6 months after sirolimus-eluting stent implantation.

Indications, complications, and short-term clinical outcome of percutaneous transvenous mitral commissurotomy.

Percutaneous transvenous mitral commissurotomy was performed in 106 consecutive patients. Significant symptomatic improvement was achieved in 97 patients (92%). Mean left atrial pressure decreased (from 18 +/- 8 to 11 +/- 8 mm Hg, p less than 0.00001), mean mitral diastolic pressure gradient decreased (from 12 +/- 7 to 7 +/- 6 mm Hg, p less than 0.00001), and mitral valve area increased (from 1.40 +/- 0.40 to 2.00 +/- 0.50 cm2, p less than 0.00001). Based on echocardiographic characteristics of the mitral apparatus, patients were grouped retrospectively in three categories: pliable (group 1, n = 37), semipliable (group 2, n = 59), and rigid (group 3, n = 10). Clinical success was achieved in 36 patients of group 1 (97%) and in 55 patients of group 2 (93%). Only six patients in group 3 (60%) improved symptomatically (p less than 0.001 vs. group 1, p less than 0.001 vs. group 2). The severity of mitral regurgitation increased in five patients of group 1 (14%), in 12 of group 2 (20%), and in three of group 3 (33%). Six patients had recurrent symptoms at 9 months after commissurotomy. Recurrence of symptoms was significantly more frequent in group 3 compared with the other two groups (group 1, 3%; group 2, 4%; and group 3, 50%; p less than 0.0001 vs. groups 1 and 2). Multiple regression analysis identified the previously mentioned echocardiographic characteristics of the mitral apparatus as the significant predictor for clinical outcome. Thus, percutaneous transvenous mitral commissurotomy can be considered a safe and effective treatment for patients with pliable valves. Patients with semipliable or with rigid valves should be selected for operation very carefully.

Percutaneous Balloon Mitral Valvuloplasty A Review

Several diseases have been acknowledged as pathological causes for mitral valve stenosis (MS), of which rheumatic heart disease is the most prevalent. Rheumatic heart disease is a chronic manifestation of rheumatic carditis, which occurs in 60% to 90% of cases of rheumatic fever. Rheumatic fever is a late sequela to Group A β-hemolytic streptococcal infection of the throat. The initial rheumatic fever results only in an edematous inflammatory process, leading to the fibrinoid necrosis of the connective tissue and cellular reactions. The initial valvulitis results in verruciform deposition of fibrin along the closing portion of the leaflets. Although all of the cardiac valves may be involved by this rheumatic process, the mitral valve is involved most prominently. The endocardial lesion most often leaves permanent sequela resulting in valvular regurgitation, stenosis, or both. Stenosis of this valve occurs from leaflet thickening, commissural fusion, and chordal shortening/fusion due to the above described pathological process. The decrease of the incidence of rheumatic heart disease in developed countries had already begun in 1910, and it is now below 1.0 per 100 000. On the other hand, the occurrence rate of rheumatic heart disease in developing countries remains substantial. Because the decline in the prevalence of rheumatic fever in industrialized nations started even before the era of penicillin and thus was related to improved living standards, the continued prevalence of rheumatic heart disease in undeveloped or developing countries is related not only to the limited availability of penicillin but to their socioeconomic status (ie, overpopulation, overcrowding, poverty, and poor access to medical care). According to the annual report by the World Heart Federation, an estimated 12 million people are currently affected by rheumatic fever and rheumatic heart disease worldwide, and high incidence rates are reported in the Southern Pacific Islands. Several studies were conducted on …

Catheter Ablation of Ectopic Atrial Tachycardia Originating from the Left Atrial Appendage using CARTOMERGE® System

A 70‐year‐old woman was referred because of drug resistant and daily incessant palpitation attack. She had undergone two previous unsuccessful radiofrequency catheter ablations at another hospital. The physical examination, chest X‐ray, and echocardiogram were all normal. The 12‐lead ECG during tachycardia showed narrow QRS, short PR tachycardia and negative polarity of the P wave in leads I and aVL (Fig. 1A). The ECG monitor showed incessant tachycardia with warming‐up phenomenon. Three dimensional electroanatomical map integrated with CT imaging (CARTOMERGE®, Biosense Webster Inc.) clearly revealed the radial activation pattern originating from the basalo‐postero‐inferior aspect of the left atrial appendage. Radiofrequency energy application at this site eliminated tachycardia permanently.