Hiroki Taguchi

Kyorin University, Tokyo, Tokyo-to, Japan

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Publications (3)12.43 Total impact

  • Article: Left ventricular dysfunction due to diffuse multiple vessel coronary artery spasm can be concealed in dilated cardiomyopathy.
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    ABSTRACT: Many patients with idiopathic dilated cardiomyopathy (DCM) have been diagnosed on the basis of the exclusion of significant coronary stenosis and the presence of left ventricular (LV) dysfunction. In the present study, we investigated the possibility that coronary multispasm is one of the mechanisms leading to diffuse idiopathic DCM-like LV dysfunction. Forty-two patients with severely depressed LV function but without significant coronary stenosis were enrolled (baseline LV ejection fraction, 33 ±11%). An acetylcholine (ACh) provocation test was performed at the time of coronary angiography. In patients with a positive ACh provocation test (n = 20), coronary angiography revealed multivessel diffuse coronary spasm with marked electrocardiogram changes. In patients with a negative ACh provocation test (n = 22), significant findings compatible with idiopathic DCM were more frequently observed on magnetic resonance imaging (MRI) or in LV biopsies compared with the ACh-positive group (MRI, 73% vs. 12%; and LV biopsy, 71% vs. 0%, respectively; P < 0.01). In the ACh-positive group, LV function significantly improved after the administration of calcium channel blockers (LV ejection fraction, 34 ±12% vs. 54 ±10%; and brain natriuretic peptide, 803 ± 482 pg/mL vs. 69 ± 84 pg/mL, at baseline and 1 year, respectively; P < 0.01). Our results raise the possibility that patients with LV dysfunction due to repeated coronary multispasm are being diagnosed as idiopathic DCM, and that calcium channel blockers may prove to be a promising therapeutic strategy in those patients.
    European Journal of Heart Failure 06/2012; 14(10):1130-8. · 4.90 Impact Factor
  • Article: Platelet level as a new prognostic factor for idiopathic pulmonary arterial hypertension in the era of combination therapy.
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    ABSTRACT: The recent development of various effective drugs, such as epoprostenol, sildenafil, and bosentan, has improved the prognosis for patients with idiopathic pulmonary arterial hypertension (IPAH). This study sought to determine survival rates and to identify predictive prognostic factors in patients with IPAH in the current era of combination therapy with new and more effective vasodilators. In 65 consecutive IPAH patients treated from 2004 to 2009, hemodynamic parameters were significantly improved and brain natriuretic peptide was significantly decreased by combination therapy (observation period: 35±18 months). The Kaplan-Meier survival curves were determined, and 22 prognostic variables, including 9 hemodynamic variables and 6 biomarkers, were evaluated to obtain the best variables. The 1-year and 3-year survival rates were 98% and 86%, respectively. Only the platelet level was correlated with death (P<0.05), and the platelet level was significantly correlated with mean pulmonary arterial pressure (P<0.01). Patients with a lower platelet level (<20×10(4)/µl (median value)) before treatment had a higher mortality rate compared to the other patients (78% vs. 95% for 3-year survival, P<0.01). Combination therapy contributed to an improvement in the prognosis of IPAH patients. Platelet level is a significant prognostic predictor in this new treatment era.
    Circulation Journal 03/2012; 76(6):1494-500. · 3.77 Impact Factor
  • Article: Impact of first-line sildenafil monotreatment for pulmonary arterial hypertension.
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    ABSTRACT: Sildenafil has been demonstrated as effective for the treatment of pulmonary arterial hypertension (PAH). The purpose of this study was to investigate the occurrence of clinical events after sildenafil monotreatment as a first-line therapy in patients with PAH over a long-term observation period. Sildenafil was administered as a first-line drug to 46 patients with PAH (including 24 patients with idiopathic PAH) during 2003-2010. We investigated subsequent clinical events such as the addition of epoprostenol, hospitalization for right-side heart failure, and death. All the hemodynamic parameters and the 6-min walk distance improved significantly in the enrolled patients as a whole receiving sildenafil treatment; 15 (33%) of the 46 patients required the addition of epoprostenol during follow-up. Kaplan-Meier analysis demonstrated that more than 60% of the patients receiving first-line sildenafil treatment did not require the addition of epoprostenol for a 5-year period. Furthermore, the 5-year survival rate after first-line sildenafil treatment was 81%. Finally, more than 75% of the enrolled patients did not reach the composite endpoint of hospitalization for right-side heart failure and death for a 5-year period. This study describes the long-term outcome of patients with PAH receiving sildenafil monotreatment as a first-line therapy and suggests that it is a promising therapeutic strategy.
    Circulation Journal 02/2012; 76(5):1245-52. · 3.77 Impact Factor