Naritatsu Saito

Long-Term Outcomes of Coronary-Artery Bypass Graft Surgery Versus Percutaneous Coronary Intervention for Multivessel Coronary Artery Disease in the Bare-Metal Stent Era

Background— Observational registries comparing coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI) have reported long-term survival results that are discordant with those of randomized trials. Methods and Results— We conducted a multicenter study in Japan enrolling consecutive patients undergoing first CABG or PCI between January 2000 and December 2002. Among 9877 patients enrolled, 5420 (PCI: 3712, CABG: 1708) had multivessel disease without left main involvement. Because age is an important determinant when choosing revascularization strategies, survival analysis was stratified by either age ≥75 or <75 years. Analyses were also performed in other relevant subgroups. Median follow-up interval was 1284 days with 95% follow-up rate at 2 years. At 3 years, unadjusted survival rates were 91.7% and 89.6% in the CABG and PCI groups, respectively (log rank P=0.26). After adjustment for baseline characteristics, survival outcome tended to be better after CABG (hazard ratio for death after PCI versus CABG [HR], 95% confidence interval [CI]: 1.23 [0.99-1.53], P=0.06). Adjusted survival outcomes also tended to be better for CABG among elderly patients (HR [95%CI]: 1.37 [0.98-1.92] P=0.07), but not among nonelderly patients (HR [95% CI]: 1.09 [0.82-1.46], P=0.55). Unadjusted and adjusted survival outcome for CABG and PCI were not significantly different in any subgroups when elderly patients were excluded from analysis. Conclusions— In the CREDO-Kyoto registry, survival outcomes among patients <75 years of age were similar after PCI and CABG, a result that is consistent with those of randomized trials.

Chronic obstructive pulmonary disease—An independent risk factor for long-term cardiac and cardiovascular mortality in patients with ischemic heart disease

BACKGROUND Limited data are available on long-term mortality and morbidity of patients with chronic obstructive pulmonary disease (COPD) and ischemic heart disease. We examined how COPD affects long-term mortality and morbidity after undergoing percutaneous coronary intervention (PCI) and coronary artery bypass grafting (CABG). METHODS We analyzed 9877 consecutive patients who underwent their first elective PCI (n=6878) and CABG (n=2999) in 2000-2002 at 30 institutions listed in the CREDO-Kyoto registry. RESULTS COPD was diagnosed in 240 patients (2.4%). In-hospital mortality (1.3% vs. 1.2%, p=0.972) did not differ between patients with and without COPD. During long-term follow-up (42. 8 month s), 906 patients (9.4%) died, 517 (5.3%) of whom died of cardiovascular death and 376 (3.9%), of cardiac death. At 3 years, the unadjusted survival rate and the rates of freedom from cardiovascular death and cardiac death were 92.1%, 95.3%, and 96.5% in the total population and 82.8%, 91.7%, and 92.1% in patients with COPD respectively. Log-rank test indicated that COPD was associated with higher incidence of all-cause mortality (p<0.0001), cardiovascular death (p=0.0002), and cardiac death (p<0.0001). Multivariate analyses indicated that COPD was an independent predictor of all-cause mortality (hazard ratio 1.36, p=0.0003), cardiovascular death (hazard ratio 1.28, p=0.0407), and cardiac death (hazard ratio 1.48, p=0.003). CONCLUSIONS COPD is an independent risk factor for long-term cardiac and cardiovascular mortality in patients with ischemic heart disease.

Clinical Impact of Left Ventricular Outflow Tract Obstruction in Takotsubo Cardiomyopathy

BACKGROUND A hyperdynamic state of the basal left ventricle sometimes results in obstruction of the left ventricular outflow tract (LVOT). However, the prevalence, clinical presentation, and prognostic effect of LVOT obstruction in takotsubo cardiomyopathy (TC) have not been fully evaluated. METHODS AND RESULTS Among 933 consecutive patients who underwent emergency coronary angiography for suspected acute coronary syndrome, 35 patients (3.8%) were diagnosed as TC. The cumulative 3-year incidence of all-cause death, cardiac death, hospitalization for congestive heart failure (CHF), and recurrent TC was 24.2%, 0.0%, 6.5%, and 12.2%, respectively. Among 27 patients with information of a LVOT pressure gradient, LVOT obstruction was present in 9 (33%). The prevalence of moderate to severe mitral regurgitation (67% vs. 11%, P=0.003), CHF (78% vs. 28%, P=0.02), and hypotension (56% vs. 5.6%, P=0.008) was significantly higher in patients with LVOT obstruction than in those without. Nevertheless, the cumulative 3-year incidence of all-cause death was not significantly different between the 2 groups (49.2% vs. 23.0%, P=0.22) with no cardiac deaths in either group. Hospitalization for CHF and recurrent TC were significantly more frequent in patients with LVOT obstruction (25.0% vs. 0.0%, P=0.04, and 25.0% vs. 6.7%, P=0.02). CONCLUSIONS In 35 consecutive patients with TC, those with significant LVOT obstruction (33%) had a more serious clinical presentation such as CHF and hypotension, but had similar 3-year mortality rate as compared with those without.

Endovascular Treatment of a Giant Aortic Arch Aneurysm With a Triple-Branched Stent Graft

An 86-year-old woman was referred for treatment of a rapidly enlarging aortic arch aneurysm, which had been monitored for 2 years with serial computed tomography (CT) scans. The size of the aneurysm had been 65 mm 2 years previously, but it had enlarged to 110 mm at the most recent examination (Figure 1). The patient complained of hemosputum and back pain. The risk of rupture was considered very high if the aneurysm was left untreated; however, thoracotomy was considered high risk because of the patient’s age. After obtaining the informed …

Microcatheter-facilitated reverse wire technique for side branch wiring in bifurcated vessels: an in vitro evaluation.

AIMS To assess when and how the microcatheter-facilitated reverse wire technique should be applied to cross the guidewire into side branches in coronary bifurcations. METHODS AND RESULTS Three interventional cardiologists with different levels of experience performed in vitro bench testing using an originally developed coronary bifurcation simulator which had six coronary bifurcations. The bifurcation angles were 90, 105, 120, 135, 150 and 165 degrees (°). Experiment 1 was conducted to assess in what coronary bifurcation the reverse wire technique is required. Antegrade guidewire advancement was conducted with two different guidewires: the spring coil guidewire SION blue and the polymer-jacket hydrophilic guidewire Fielder FC. Experiment 2 was conducted to determine what the optimal guidewire selection and the optimal guidewire shape for the reverse wire technique would be. Assessment of the guidewire crossability into the highly angulated side branch was performed, and then the balloon crossability was assessed. A total of four guidewire types were compared in experiment 2. In experiment 1, guidewire crossing was impossible by conventional antegrade wiring when the bifurcation angle became 150° or more. In experiment 2, guidewire crossing of more than 150° of bifurcation angle was achievable independent of the guidewire types and shape. Balloon deliverability was best when using a polymer-jacket hydrophilic guidewire with a round shape 3 cm from the guidewire tip. CONCLUSIONS Although the guidewire crossing into the side branch was impossible by conventional antegrade methods when the bifurcation angle became 150° or more, the guidewire crossing into such a highly angulated side branch was easily possible using the reverse wire technique. The optimal guidewire selection for the reverse wire technique is the polymer-jacket hydrophilic guidewire with a round shape 3 cm from the guidewire tip.

Excimer Laser–assisted Retrieval of Günther Tulip Vena Cava Filters: A Pilot Study in a Canine Model

PURPOSE Although most Günther Tulip filters (GTFs) can be safely retrieved within a few months after implantation, their recommended safe retrieval period is within a few weeks. This study aims to assess the feasibility of excimer laser-assisted retrieval of GTFs incorporated into the inferior vena cava (IVC) wall in a canine model. MATERIALS AND METHODS Six GTFs were implanted in six mongrel dogs and retrieved after four weeks. The retrieval system consisted of a 14-F excimer laser sheath, an 8-F guide catheter, and a 15-mm Goose Neck snare. RESULTS All filters were tightly fixed to the IVC wall. After ablation of the adhesions by excimer laser emission, all filters were successfully retrieved. Final cavography after retrieval revealed no caval damage except for minor extravasation in three dogs. Examination of the caval specimen taken from a dog immediately after filter retrieval revealed partial absence of the intima and media. In the remaining five dogs, cavography performed 2 days after filter retrieval revealed complete hemostasis and almost indistinguishable intimal indentations. On follow-up cavography 28 days after filter retrieval, caval stenosis with 38% +/- 11% diameter narrowing was noted. The caval specimen obtained from a dog at 28 days showed neointima formation at the level where the filter struts were in contact with the caval wall. The other four dogs have survived for more than 3 months without any adverse events. CONCLUSIONS Laser-assisted retrieval of a GTF incorporated into the IVC wall is feasible in dogs.

Percutaneous balloon valvuloplasty for bioprosthetic mitral valve stenosis

Percutaneous transcatheter mitral valvuloplasty is the indicated treatment of choice for symptomatic native mitral valve stenosis, but there have been limited reports of successful procedures of balloon valvuloplasty for bioprosthetic mitral valve stenosis. We present the case of a 62-year-old woman suffering from progressive dyspnea due to bioprosthetic mitral valve stenosis. The measured mean pressure gradient across the mitral valve was 30 mmHg and the mitral valve area was 0.73 cm2. Redoing mitral replacement was considered high risk and was refused by the patient. Percutaneous balloon valvuloplasty was performed with an Inoue balloon catheter inflated to 20 mm. The patient’s symptoms immediately improved after the procedure, with no procedure-related complications. The mean pressure gradient across the valve decreased to 19 mmHg, and the mitral valve area increased to 1.21 cm2 in postprocedural echocardiography. We conducted a literature search and identified 26 cases of balloon valvuloplasty for degenerated bioprosthetic valves. Of these, 14 cases were bioprosthetic mitral valves, and the results were favorable. However, more case reports are required to establish an evidence base for future expert recommendation of balloon valvuloplasty of prosthetic mitral valve. Meanwhile, balloon valvuloplasty will serve a niche role in highly selected patients with prosthetic mitral valve stenosis.

Favorable Clinical Outcomes of Transcatheter Aortic Valve Implantation in Japanese Patients ― First Report From the Post-Approval K-TAVI Registry ―

BACKGROUND Very limited data exist on the outcomes of transcatheter aortic valve implantation (TAVI) since Japanese marketing approval of the first TAVI device.Methods and Results:The Kyoto University-related hospital Transcatheter Aortic Valve Implantation (K-TAVI) registry includes prospectively collected data from 6 participating hospitals in Japan. We included 302 patients with severe aortic stenosis who underwent TAVI using the SAPIEN XT balloon-expandable valve via transfemoral (TF; n=203, 67%) or transapical (TA; n=99, 33%) approach between October 2013 and September 2015. Device success rate, based on the Valve Academic Research Consortium-2 criteria, was very high in the TF (97.0%) and TA (99.0%) groups. The 30-day mortality rates were 1.5% and 1.0% in the TF and TA groups, respectively. Major complications included stroke (transient or persistent: 2.3%), annulus rupture (1.0%), coronary intervention (1.0%), major vascular complications (1.7%), and permanent pacemaker implantation (5.4%). The procedure times of the post-proctoring period (n=210) were decreased compared with those of the proctoring period (n=89) without affecting the clinical outcomes. The survival rates at 6 and 12 months were 96.9% and 92.5% in the TF group, and 93.9% and 91.8% in the TA group, respectively. CONCLUSIONS The K-TAVI registry data revealed that the early outcomes of TAVI using the SAPIEN XT were favorable in real-world Japanese patients.

Prediction of the true fractional flow reserve of left main coronary artery stenosis with concomitant downstream stenoses: in vitro and in vivo experiments.

AIMS The functional impact of downstream coronary stenoses on left main coronary artery (LMCA) stenosis has not been fully elucidated. This study therefore aimed to use in vitro and in vivo experiments to assess two novel equations that predict the true fractional flow reserve (FFR) of a left main coronary artery (LMCA) stenosis with concomitant downstream stenoses. METHODS AND RESULTS Two novel equations were derived. One equation predicts the true fractional flow reserve (FFR) of an LMCA stenosis with a downstream stenosis (Equation A), and the other predicts the true FFR of an LMCA stenosis with downstream stenoses in both the left anterior descending and left circumflex arteries (Equation B). The equations were validated in both in vitro and in vivo models of the coronary circulation. The agreements between the apparent FFR (FFRapp), the predicted FFR (FFRpred) and the true FFR (FFRtrue) were assessed by Passing-Bablok regression analysis. Passing-Bablok regression analysis revealed that there were fixed proportional errors between FFRapp-m and FFRtrue-m, though a very small fixed error and no proportional errors between FFRpred-m and FFRtrue-m. The absolute differences between FFRpred and FFRtrue were significantly lower as compared to those between FFRapp and FFRtrue in all experiments. CONCLUSIONS Two novel equations which predict the true FFR of LMCA stenosis were demonstrated to be correct. The study also revealed that the functional impact of downstream stenoses on the LMCA stenosis became stronger when the downstream stenoses became more severe.

Prevention of neointimal formation using miRNA-126-containing nanoparticle-conjugated stents in a rabbit model

Background Despite recent progress with drug-eluting stents, restenosis and thrombosis after endovascular intervention are still major limitations in the treatment of cardiovascular diseases. These problems are possibly caused by inappropriate inhibition of neointimal formation and retardation of re-endothelialization on the surface of the stents. miR-126 has been shown to have the potential to enhance vascular endothelial cell proliferation. Methods and results We designed and constructed a 27-nt double strand RNA (dsRNA) conjugated to cholesterol, which has high membrane permeability, and formed mature miR-126 after transfection. For site-specific induction of miR-126, we utilized poly (DL-lactide-co-glycolide) nanoparticles (NPs). miR-126-dsRNA-containing NPs (miR-126 NPs) significantly reduced the protein expression of a previously identified miR-126 target, SPRED1, in human umbilical vascular endothelial cells (HUVECs), and miR-126 NPs enhanced the proliferation and migration of HUVECs. On the other hand, miR-126 NPs reduced the proliferation and migration of vascular smooth muscle cells, via the suppression of IRS-1. Finally, we developed a stent system that eluted miR-126. This delivery system exhibited significant inhibition of neointimal formation in a rabbit model of restenosis. Conclusions miR-126 NP-conjugated stents significantly inhibited the development of neointimal hyperplasia in rabbits. The present study may indicate the possibility of a novel therapeutic option to prevent restenosis after angioplasty.