High-power and high-efficiency operation of 1.3 µm-wavelength InP-based photonic-crystal surface-emitting lasers with metal reflector.

We demonstrate high-output-power and high-efficiency operation of 1.3-µm-wavelength InP-based photonic-crystal surface-emitting lasers (PCSELs). By introducing a metal reflector and adjusting the phase of the reflected light via optimization of the thickness of the p-InP cladding layer, we successfully achieve an output power of approximately 400 mW with the slope efficiency of 0.4 W/A and the wall-plug efficiency of 20% under CW conditions. In addition, this PCSEL exhibits a narrow circular beam with a divergence angle below 1.6° even at high output powers under CW conditions at temperatures from 15°C to 50°C. We have also demonstrated an output power of over 12 W under pulsed conditions at room temperature.

Life Expectancy of Patients With Severe Aortic Stenosis in Relation to Age and Surgical Risk Score.

BACKGROUND: There is a paucity of data regarding shorter life expectancy after aortic valve replacement (AVR) in patients with severe aortic stenosis (AS). METHODS: Among 3815 patients with severe AS enrolled in the CURRENT AS (Contemporary outcomes after sURgery and medical tREatmeNT in patients with severe Aortic Stenosis) registry, there were 1469 patients (initial AVR: n = 647; conservative strategy: n = 822) with low surgical risk, 1642 patients (initial AVR: n = 433; conservative strategy: n = 1209) with intermediate surgical risk, and 704 patients (initial AVR: n = 117; conservative strategy: n = 587) with high surgical risk. Among 1163 patients who actually underwent surgical AVR as the initial strategy, patients were divided into 4 groups according to age <65 years (n = 185), 65 to 74 (n = 394), 75 to 80 (n = 345), and >80 (n = 239). The expected survival of the general Japanese population was obtained from the Statistics Bureau of Japan. The surgical risk was estimated using The Society of Thoracic Surgery (STS) score. RESULTS: The median follow-up was 3.7 years. The cumulative incidences of all-cause death were significantly lower in the initial AVR strategy than in the initial conservative strategy across the 3 STS groups. Shorter life expectancy after surgical AVR was seen especially in younger patients. The observed mortality in low-risk patients was comparable to the expected mortality across all the age-groups, while intermediate-risk patients aged <75 years, and high-risk patients across all age-groups had higher mortality compared with the expected mortality. CONCLUSIONS: The risk stratification according to age and STS score might be useful to estimate shorter life expectancy after AVR, and these findings have implications for decision making in the choice of surgical or transcatheter AVR.

High-power CW oscillation of 1.3-µm wavelength InP-based photonic-crystal surface-emitting lasers.

We demonstrate high-power continuous-wave (CW) lasing oscillation of 1.3-µm wavelength InP-based photonic-crystal surface-emitting lasers (PCSELs). Single-mode operation with an output power of over 100 mW, a side-mode suppression ratio (SMSR) of over 50 dB, and a narrow single-lobe beam with a divergence angle of below 1.2° are successfully achieved by using a double-lattice photonic crystal structure consisting of high-aspect-ratio deep air holes. The double lattice is designed to enhance both the in-plane optical feedback and the surface radiation effects in the photonic crystal. The coupling coefficients for 180 ∘, +90 ∘, and -90 ∘ diffractions are estimated from the measurements of the photonic band structure as κ1D = 417 cm-1, κ2D+ = 135 cm-1, and κ2D- = 65 cm-1, respectively. The stable single-mode, high-beam-quality operation is attributed to these large coupling coefficients introduced by the asymmetric double-lattice structure.

Mid-Term Patency of Spiral Saphenous Vein Graft for Malignant Superior Vena Cava Syndrome.

Reports documenting the mid-term patency of spiral saphenous vein grafts for superior vena cava syndrome in patients with advanced thoracic malignancy are, so far, scarce. The present report describes a 69-year-old man who suffered superior vena cava syndrome due to malignant invasion by advanced lung cancer. Since the huge mass in the anterior mediastinum was unresectable, a bypass from the left innominate vein to the right atrium using an autologous spiral saphenous vein graft was surgically created. Postoperatively, the patient received chemoradiotherapy and maintenance anticoagulant therapy, resulting in survival for 4 years without graft occlusion or recurrence of superior vena cava syndrome.

Continous-wave lasing operation of 1.3-µm wavelength InP-based photonic crystal surface-emitting lasers using MOVPE regrowth.

We report on electrically driven InP-based photonic-crystal surface-emitting lasers (PCSELs), which possess a deep-air-hole photonic crystal (PC) structure underneath an active region formed by metal-organic vapor-phase-epitaxial (MOVPE) regrowth. Single-mode continuous-wave (CW) lasing operation in 1.3-µm wavelength is successfully achieved at a temperature of 15°C. It is shown that the enhancement of lateral growth during the MOVPE regrowth process of air holes enables the formation of deep air holes with an atomically flat and thin overlayer, whose thickness is less than 100 nm. A threshold current of 120 mA (threshold current density = 0.68 kA/cm2) is obtained in a device with a diameter of 150 µm. A doughnut-like far-field pattern with the narrow beam divergence of less than 1° is observed. Strong optical confinement in the PC structure is revealed from measurements of the photonic band structure, and this strong optical confinement leads to the single-mode CW lasing operation with a low threshold current density.

Hybrid Repair for Mega-Aortic Syndrome due to Giant Cell Aortitis in a Heart Failure Patient.

The present report describes a case of mega-aortic syndrome accompanied with severe aortic regurgitation in a 75-year-old man who underwent a two-stage hybrid repair. Intraoperative pathologic findings at the first repair, consisting of Bentall operation and total arch replacement with a Lupiae graft, aided the identification of the giant cell aortitis. Despite complicating hemorrhagic stroke, steroid therapy was initiated and endovascular repair was subsequently completed. Over more than 2 years of follow-up, the patient continued steroid therapy and is doing well without any reintervention.

Antegrade thoracic endovascular aneurysm repair via the ascending aorta.

PURPOSE: We performed antegrade thoracic endovascular aneurysm repair via the ascending aorta in selected high-risk patients scheduled for open surgery, in whom an iliofemoral or abdominal aortic approach was not feasible. We present our initial experience with this approach. METHODS: Of 16 consecutive patients who underwent antegrade endovascular aneurysm repair via the ascending aorta at our institution, 3 had an emergency intervention for rupture and 3 had an urgent intervention for impending rupture or complicated aortic dissection. The procedure was scheduled in 10 patients. The median patient age was 77 years. In 13 patients, one or more concomitant procedures were performed. In 6 patients, vascular access for endovascular aneurysm repair was obtained via a branch of the replacement graft. In 10 patients, direct cannulation of the ascending aorta was carried out using 2 pursestring sutures. RESULTS: The initial success rate was 100%. Early mortality occurred in 2 (12.5%) patients because of multiple organ failure in one and heart failure in the other. No patient required a second intervention during follow-up. The mean duration of follow-up was 19 months. CONCLUSION: The antegrade approach is a useful alternative in patients with no access suitable for endovascular aneurysm repair and who are not appropriate candidates for open conventional thoracic aortic surgery. This approach is applicable to selected patients.

Cusp-Level Chordal Shortening for Non-Rheumatic Mitral Anterior Leaflet Prolapse in a Patient with Persistent Atrial Fibrillation.

The case is reported of mitral valve repair with cusp-level chordal shortening for non-rheumatic mitral anterior leaflet prolapse. The simple and easily reproducible cusp-level shortening procedure consists of plication of the redundant chorda underneath the leaflet. Provided the chorda is thick enough, this procedure is more likely to be applied to regional mitral anterior prolapse due to elongation of the chorda, even in patients with non-rheumatic heart disease. The present patient underwent perioperative adaptive servo-ventilation (ASV) therapy. ASV might help to prevent atrial fibrillation recurrence after the Maze procedure by reducing sympathetic overactivity, contributing to the durability and outcome of mitral valve repair with cusp-level chordal shortening.

Symmetrical papillary muscle approximation for functional mitral regurgitation with idiopathic dilated cardiomyopathy.

The cases are reported of mitral valve repair with symmetrical papillary muscle approximation from heads to bases close to cardiac apex for functional mitral regurgitation (FMR). The two papillary heads attaching the chordae to both leaflets from the posteromedial papillary muscle were approximated parallel to the solitary head of the anterolateral papillary muscle. This procedure permits an even reduction of lateral shift of the papillary muscle, resulting in an elimination of mitral tethering, and provides a satisfactory and durable mitral valve repair with good outcomes in patients with idiopathic dilated cardiomyopathy and FMR.

[Cardiac perforation with a passive fixation lead penetrating ventricular septum; report of a case].

A 81-year-old female developed diaphragm twitching 2 days after the intravenous implantation of pacemaker (DDD mode) with passive fixation leads. A computed tomography (CT) and fluoroscopy revealed the lead perforating the interventricular septum and the ventricular wall without any sign of pericardial effusion. Surgical procedure through median sternotomy was performed, and the penetrated lead was removed. The injured myocardium was repaired with a U stitch reinforced by Teflon-feltstrips. New epicardial leads were fixed on the right atrial wall and on the inferior wall of the right ventricle. The patient had been doing well until 86-year-old, when she died of myelodysplastic syndrome.

Successful closure of a patent ductus arteriosus using an aortic stent graft.

Closure of patent ductus arteriosus (PDA) in the elderly is a high-risk procedure due to the fragility of the aorta and aneurysmal changes in the ductus. Stent grafting has emerged as a method for treating aortic disease. We describe a case in which this endovascular technique was successfully performed for closure of a PDA with aneurismal change in a high-risk patient. This approach may comprise the armamentarium for treating this pathology in adults.

[Application of partial median sternotomy in cardiac surgery in patients with tracheostoma].

Median full-sternotomy carries a risk of sternal infection and lethal mediastinitis in cardiac surgery. We performed open-heart surgery through partial median sternotomy in 5 patients with tracheostomy. Coronary artery bypass grafting (CABG) was performed in 3 patients, aortic valve replacement in 1, and mitral valve replacement in 1. No operative deaths or complications related to wound infection occurred. Partial sternotomy represents a safe alternative in cardiac surgery in patients with tracheostoma.