Sumio Mizuno

Quantitative approach to the histopathology of the biopsied right ventricular myocardium in patients with diabetes mellitus

SummaryFor the purpose of studying the clinicopathology of the biopsied myocardium in patients with diabetes mellitus, the diameter of right ventricular myocardial cells and diffuse perimysial fibrosis of biopsied myocardium were measured quantitatively. Seven healthy controls and nine diabetic patients without hypertension or coronary arterial disease were subjected to this study. The degree of diabetic complications was mild to moderate. The diameter of myocardial cells was measured and the degree of diffuse perimysial fibrosis was assessed by the point-counting method using a square grid, in which the distance between the points was 10 µm. Over 2000 points which lay on the longitudinally cut myocardial cells and on the interstitial fibrosis stained by the Mallory-Azan method were measured. Percentage fibrosis was calculated according to the formula: percentage fibrosis=(points lying on the interstitial fibrosis)/[(points lying on the myocardial cell)+(points lying on the interstitial fibrosis)] × 100. The results were as follows. The mean diameter of right ventricular myocardial cells in patients with diabetes mellitus was significantly larger than that of controls (P<0.01). The percentage fibrosis of diabetic patients was significantly higher than that of controls (P<0.01). There was no significant correlation between the histopathological measurements and clinical features. It is concluded that hypertrophy of myocardial cells and interstitial fibrosis of the myocardium exist even in mild diabetes mellitus.

Effects of Troglitazone on Frequency of Coronary Vasospastic-Induced Angina Pectoris in Patients With Diabetes Mellitus

This study investigates the effects of troglitazone, an insulin sensitizer, on the clinical manifestation of coronary vasospastic angina pectoris in patients with diabetes mellitus. Troglitazone reduces frequency of angina pectoris and improves endothelial function.

Intracoronary aspiration thrombectomy for acute myocardial infarction.

To investigate the pathogenesis of acute myocardial infarction (AMI) and values of intracoronary aspiration thrombectomy (ICAT), we applied ICAT to reperfusion therapy using generally available intracoronary catheters to aspirate intracoronary occlusive tissues. We assigned ICAT or primary percutaneous transluminal coronary angioplasty (PTCA) to patients with evolving AMI (Thrombolysis In Myocardial Infarction (TIMI) trial grade 0), and investigated primary histopathologic, clinical, and angiographic outcomes in 43 patients treated with ICAT alone or followed by PTCA, and compared the outcomes with those in 48 patients treated with primary PTCA. No major complications (procedural death, emergent bypass graft surgery) occurred. Reconalization (TIMI grade 3 and 2) was achieved in 25 patients (58%) with ICAT alone and in 39 patients (91%) with ICAT alone or followed by PTCA. Aspirated thrombi were defined as recent thrombi in 21 cases (49%), atheroma in 6 (14%), no thrombi in 13 (30%), and organized thrombi in 1 case. In cases of recent thrombi, ICAT alone provided recanalization more frequently than in those of atheroma or no thrombi (18 of 21 [86%], 3 of 6 [50%], 4 of 13 [31%], respectively; p < 0.05; recent thrombi vs atheroma or no thrombi). There were no significant differences in primary recanalization rate (ICAT alone or followed by PTCA vs primary PTCA; 91% vs 92%) or incidence of complications between the 2 strategies. These results indicate that although the pathogenesis of AMI is heterogeneous in each individual case, intracoronary thrombus contributes little to the pathogenesis of average AMI, and therefore mechanical approaches may be feasible to maximize reperfusion therapies for AMI.

Impact of severe coronary disease associated or not associated with diabetes mellitus on outcome of interventional treatment using stents: results from HERZ (Heart Research Group of Kanazawa) analyses.

Percutaneous coronary intervention (PCI) using a drug-eluting stent (DES) leads to less re-stenosis than PCI using a bare metal stent (BMS), however there is still controversy whether use of a DES for severe coronary disease leads to an acceptable outcome in patients with diabetes mellitus (DM). In this study 8159 lesions were treated in 6739 patients (mean age 68.9 years) with coronary artery disease. Use of a DES significantly decreased the re-stenosis rate compared with BMS in both DM (9.6% versus 21.3%) and non-DM (9.5% versus 17.1%) patients. The re-stenosis rate was significantly higher in DM than in non-DM patients in the BMS group but not in the DES group. There was no statistically significant difference in event-free survival after stenting of patients with left main coronary artery (LMCA) disease between the BMS and DES groups. It was concluded that, compared with BMS, DES reduced re-stenosis in patients with DM, however, we advise careful treatment after using DES for severe coronary disease, including LMCA lesions, in patients with DM.

CVIT expert consensus document on primary percutaneous coronary intervention (PCI) for acute myocardial infarction (AMI) in 2018

While primary percutaneous coronary intervention (PCI) has significantly contributed to improve the mortality in patients with ST segment elevation myocardial infarction even in cardiogenic shock, primary PCI is a standard of care in most of Japanese institutions. Whereas there are high numbers of available facilities providing primary PCI in Japan, there are no clear guidelines focusing on procedural aspect of the standardized care. Whilst updated guidelines for the management of acute myocardial infarction were recently published by European Society of Cardiology, the following major changes are indicated; (1) radial access and drug-eluting stent over bare metal stent were recommended as Class I indication, and (2) complete revascularization before hospital discharge (either immediate or staged) is now considered as Class IIa recommendation. Although the primary PCI is consistently recommended in recent and previous guidelines, the device lag from Europe, the frequent usage of coronary imaging modalities in Japan, and the difference in available medical therapy or mechanical support may prevent direct application of European guidelines to Japanese population. The Task Force on Primary Percutaneous Coronary Intervention of the Japanese Association of Cardiovascular Intervention and Therapeutics (CVIT) has now proposed the expert consensus document for the management of acute myocardial infarction focusing on procedural aspect of primary PCI.