Kenji Yamabe

Pioglitazone reduces neointimal tissue proliferation after coronary stent implantation in patients with type 2 diabetes mellitus: an intravascular ultrasound scanning study

BACKGROUND It has been reported that pioglitazone reduces neointimal hyperplasia after balloon-induced vascular injury in an experimental model. METHODS To determine whether pioglitazone reduces neointimal tissue proliferation after coronary stent implantation in patients with type 2 diabetes mellitus, we studied 44 stented lesions in 44 patients with diabetes mellitus who underwent successful coronary stent implantation. Study patients were randomized into 2 groups: the pioglitazone group (23 patients with 23 lesions) and the control group (21 patients with 21 lesions). All patients underwent serial quantitative coronary angiography and serial intravascular ultrasound scanning studies. With a motorized pullback system, multiple image slices within the stent were obtained at every 1 mm. The stent area and lumen area were measured, and the neointimal area was calculated. Measurements were averaged over the number of selected image slices. The neointimal index was calculated as the averaged neointimal area divided by the averaged stent area multiplied by 100 (%). RESULTS After 6 months of treatment, angiographic in-stent restenosis (17% vs 43%, respectively, P =.0994) and target lesion revascularization (13% vs 38%, respectively, P =.0835) were less frequent in the pioglitazone group than the control group; however, these differences did not reach significance. The intravascular ultrasound scanning study demonstrated that the neointimal index in the pioglitazone group was significantly smaller than that in the control group (28% +/- 9% vs 48% +/- 15%, respectively, P <.0001). CONCLUSION A serial intravascular ultrasound scanning assessment demonstrated that pioglitazone reduces neointimal tissue proliferation after coronary stent implantation in patients with type 2 diabetes mellitus.

Coronary Flow Velocity Pattern Immediately After Percutaneous Coronary Intervention as a Predictor of Complications and In-Hospital Survival After Acute Myocardial Infarction

Background—Recently, it was reported that the degree of microvascular injury and left ventricular functional recovery during the chronic period can be predicted after treatment of the infarct-related artery based on the coronary flow velocity (CFV) pattern assessed using a Doppler guidewire. The aim of this prospective study was to examine whether the CFV pattern may predict complications and in-hospital survival after acute myocardial infarction (AMI). Methods and Results—The study population consisted of 169 consecutive patients with a first anterior AMI successfully treated with percutaneous coronary intervention (PCI). We examined the CFV pattern immediately after PCI using a Doppler guidewire. In accordance with previous findings, we defined severe microvascular injury as a diastolic deceleration time ≤600 ms and the presence of systolic flow reversal. Patients were divided into two groups: those without severe microvascular injury (n=118; group 1) and those with severe microvascular injury (n=51; group 2). All of the patients who had cardiac rupture were in group 2. Congestive heart failure (CHF) was observed more frequently in group 2 than in group 1 (53% versus 8%, P <0.001). The in-hospital cardiac mortality rate was significantly higher in group 2 than in group 1 (18% versus 0%, P <0.001). Nine patients in group 2 died, 5 patients because of CHF and 4 patients because of cardiac rupture. Conclusions—These findings suggest that the CFV pattern is an accurate predictor of the presence or absence of complications and of in-hospital survival after AMI.

Impact of troglitazone on coronary stent implantation using small stents in patients with type 2 diabetes mellitus

In summary, troglitazone reduces angiographic in-stent restenosis and target lesion revascularization rates after coronary stent implantation using 2.5-mm stents in patients with type 2 DM. Serial IVUS assessment demonstrates that the reduction in neointimal tissue proliferation in the troglitazone group is associated with the angiographic results.

Prognosis of Retrograde Dissection From the Descending to the Ascending Aorta

Background—Natural history of aortic dissection (AD) with intimal tear in the descending or abdominal aorta and retrograde extension into the ascending aorta (retrograde AD) remains unknown. The purpose of this study was to elucidate medium-term prognosis of patients with retrograde AD. Methods and Results—Study population consisted of 109 patients with acute type A AD. There were 27 patients (25%) with retrograde AD and 82 patients (75%) with intimal tear in the ascending aorta (antegrade AD). In antegrade AD patients, 60 patients underwent surgery and 22 patients were treated medically. In retrograde AD patients, 14 patients showed localized crescentic high attenuation area along the ascending aortic wall without enhancement in computed tomography. Transesophageal echocardiography revealed complete thrombosis of false lumen (FL) in the ascending aorta (retrograde thrombosed). The remaining 13 patients showed incomplete or no thrombosis (retrograde nonthrombosed). All retrograde nonthrombosed AD patients underwent surgery except for 1 patient with stroke, whereas all retrograde thrombosed AD patients were treated medically. In-hospital mortality rate of retrograde AD patients was significantly lower than that of antegrade AD patients (15% versus 38%, P =0.027). The survival rates in retrograde AD patients were all 85% at 1, 2, and 5 years, which were significantly higher than those of antegrade AD patients (63%, 62%, and 57%, respectively)(P =0.009). Conclusions—Patients with type A retrograde AD have better medium-term prognosis than patients with antegrade AD. Retrograde AD patients with thrombosed FL in the ascending aorta could be treated medically with timed surgical repair.

Noninvasive assessment of flow velocity and flow velocity reserve in the right gastroepiploic artery graft by transcutaneous Doppler echocardiography: comparison with an invasive technique.

BACKGROUND The measurement of flow velocity (FV) in coronary artery bypass grafts using a Doppler guidewire has provided useful clinical and physiologic information. The recently developed transcutaneous Doppler echocardiography is a noninvasive technique to measure FV and FV reserve (FVR) in the right gastroepiploic artery (GEA) graft. The purpose of this study was to evaluate whether transcutaneous Doppler echocardiography accurately measures FV and FVR in the right GEA graft in a clinical setting. METHODS In 33 patients who underwent graft angiography for the assessment of the right GEA graft, FV in the right GEA graft was measured by transcutaneous Doppler echocardiography under the guidance of color flow Doppler imaging at the time of examination using a Doppler guidewire. FV in the midportion of the right GEA graft was measured at baseline and during hyperemic conditions using both transcutaneous Doppler echocardiography and a Doppler guidewire. RESULTS There were excellent correlations between the value of FV obtained by transcutaneous Doppler echocardiography and those obtained with the Doppler guidewire (averaged peak velocity: y = 0.95 x + 1.46, r = 0.98, standard error of the estimate [SEE] = 2.94 cm/s; averaged systolic peak velocity: y = 0.94 x + 1.18, r = 0.97, SEE = 3.15 cm/s; diastolic peak velocity: y = 0.97 x + 1.62, r = 0.98, SEE = 4.40 cm/s; averaged diastolic peak velocity: y = 0.95 x + 1.75, r = 0.98, SEE = 3.60 cm/s). The FVR as determined by transcutaneous Doppler echocardiography showed a good correlation with that determined using the Doppler guidewire method (y = 0.90 x + 0.21, r = 0.92, SEE = 0.31). CONCLUSIONS Transcutaneous Doppler echocardiography proved to be an accurate noninvasive method to measure FV and FVR in the right GEA graft.