Akiko Tanaka

The Subclavian Intraaortic Balloon Pump: A Compelling Bridge Device for Advanced Heart Failure

BACKGROUND A subclavian intraaortic balloon pump (SC-IABP) can help to optimize patients with advanced congestive heart failure as a bridge to definitive therapy. We retrospectively reviewed our experience to assess the application and safety of this technique. METHODS We studied 88 patients with decompensated advanced congestive heart failure who received SC-IABP placement between January 2011 and December 2014. The SC-IABP was placed through a graft in the subclavian artery. The intended therapeutic goals for SC-IABP were bridge to transplant (n = 61), mechanical circulatory support (n = 21), or recovery (n = 6). Success was defined as stroke-free survival, achievement of therapeutic goal, and maintenance or improvement in renal function, hemodynamics, and physical conditioning through ambulation and rehabilitation. RESULTS Eighty patients were successfully bridged to the next therapy (transplant 93.4%, mechanical circulatory support 95.3%, recovery 50%). There was no mortality related to SC-IABP placement. Duration of SC-IABP support was 4 to 135 days (median 21). Failure was attributed to escalation of support (n = 5), stroke (n = 2), and sepsis (n = 1). Mean pulmonary artery pressure significantly improved from 33 ± 11 mm Hg to 28 ± 8 mm Hg (p < 0.05). Eighty-four patients (95.5%) ambulated more than 3 times a day. Two-minute step test demonstrated significant improvement, from 50 ± 9 steps to 90 ± 23 steps (n = 16, p < 0.001). Specific complications of SC-IABP included exchange/repositioning (n = 26, 29.5%), subclavian artery thrombosis (n = 1, 1.1%), and reexploration for hematoma (n = 4, 4.5%) and infection (n = 2, 2.3%). No distal thromboembolic events were observed. CONCLUSIONS The SC-IABP provided excellent hemodynamic support with minimal morbidity and mortality, allowed for extensive rehabilitation, and permitted more than 90% of patients to receive their intended therapy. Therefore, SC-IABP is a compelling bridge device for patients with advanced congestive heart failure.

A fast, noniterative approach for accelerated high‐temporal resolution cine‐CMR using dynamically interleaved streak removal in the power‐spectral encoded domain with low‐pass filtering (DISPEL) and modulo‐prime spokes (MoPS)

Purpose To introduce a pair of accelerated non‐Cartesian acquisition principles that when combined, exploit the periodicity of k‐space acquisition, and thereby enable acquisition of high‐temporal cine Cardiac Magnetic Resonance (CMR). Methods The mathematical formulation of a noniterative, undersampled non‐Cartesian cine acquisition and reconstruction is presented. First, a low‐pass filtering step that exploits streaking artifact redundancy is provided (i.e., Dynamically Interleaved Streak removal in the Power‐spectrum Encoded domain with Low‐pass filtering [DISPEL]). Next, an effective radial acquisition for the DISPEL approach that exploits the property of prime numbers is described (i.e., Modulo‐Prime Spoke [MoPS]). Both DISPEL and MoPS are examined using numerical simulation of a digital heart phantom to show that high‐temporal cine‐CMR is feasible without removing physiologic motion vs aperiodic interleaving using Golden Angles. The combined high‐temporal cine approach is next examined in 11 healthy subjects for a time–volume curve assessment of left ventricular systolic and diastolic performance vs conventional Cartesian cine‐CMR reference. Results The DISPEL method was first shown using simulation under different streak cycles to allow separation of undersampled radial streaking artifacts from physiologic motion with a sufficiently frequent streak‐cycle interval. Radial interleaving with MoPS is next shown to allow interleaves with pseudo‐Golden‐Angle variants, and be more compatible with DISPEL against irrational and nonperiodic rotation angles, including the Golden‐Angle‐derived rotations. In the in vivo data, the proposed method showed no statistical difference in the systolic performance, while diastolic parameters sensitive to the cines temporal resolution were statistically significant (P < 0.05 vs Cartesian cine). Conclusions We demonstrate a high‐temporal resolution cine‐CMR using DISPEL and MoPS, whose streaking artifact was separated from physiologic motion.

A novel profile/view ordering with a non‐convex star shutter for high‐resolution 3D volumetric T1 mapping under multiple breath‐holds

To examine a novel non‐convex star ordering/shutter for reducing the number of breath‐holds in cardiac three‐dimensional (3D) T1 Mapping MRI with multiple breath‐holds.

3D late gadolinium enhanced cardiovascular MR with CENTRA-PLUS profile/view ordering: Feasibility of right ventricular myocardial damage assessment using a swine animal model

AIMS To develop a high-resolution, 3D late gadolinium enhancement (LGE) cardiovascular magnetic resonance imaging (MRI) technique for improved assessment of myocardial scars, and evaluate its performance against 2D breath-held (BH) LGE MRI using a surgically implanted animal scar model in the right ventricle (RV). METHODS AND RESULTS A k-space segmented 3D LGE acquisition using CENTRA-PLUS (Contrast ENhanced Timing Robust Acquisition with Preparation of LongitUdinal Signal; or CP) ordering is proposed. 8 pigs were surgically prepared with cardiac patch implantation in the RV, followed in 60days by 1.5T MRI. LGE with Phase-Sensitive Inversion Recovery (PSIR) were performed as follows: 1) 2DBH using pneumatic control, and 2) navigator-gated, 3D free-breathing (3DFB)-CP-LGE with slice-tracking. The animal heart was excised immediately after cardiac MR for scar volume quantification. RV scar volumes were also delineated from the 2DBH and 3DFB-CP-LGE images for comparison against the surgical standard. Apparent scar/normal tissue signal-to-noise ratio (aSNR) and contrast-to-noise ratio (aCNR) were also calculated. 3DFB-CP-LGE technique was successfully performed in all animals. No difference in aCNR was noted, but aSNR was significantly higher using the 3D technique (p<0.05). Against the surgical reference volume, the 3DFB-CP-LGE-derived delineation yielded significantly less volume quantification error compared to 2DBH-derived volumes (15±10% vs 55±33%; p<0.05). CONCLUSION Compared to conventional 2DBH-LGE, 3DFB-LGE acquisition using CENTRA-PLUS provided superior scar volume quantification and improved aSNR.

The extracellular matrix patch implanted in the right ventricle evaluated with cardiovascular magnetic resonance protocol to assess regional physio-mechanical properties

OBJECTIVES An extracellular matrix patch was implanted in the porcine right ventricle for in situ myocardial regeneration. A newly developed cardiovascular magnetic resonance protocol was utilized to investigate the regional physio-mechanical function of the patch. METHODS Cardiovascular magnetic resonance was performed at 60-day after the porcine right ventricular wall full thickness substitution with an extracellular matrix cardiac patch (n = 5). Dacron patches and remote normal right ventricle served as control (n = 5/each). Late gadolinium enhancement, strain encoding and rest perfusion were measured for scar/patch detection, regional contractility and tissue perfusion. Image analyses were performed by two observers to validate interobserver reproducibility. RESULTS All imaging sequences were successfully obtained. The patches were located with late gadolinium enhancement imaging in 95% accuracy. All the parameters demonstrated significant differences among extracellular matrix, Dacron and normal myocardium (P < 0.05), which correlated with histological findings, including constructive remodelling with nascent myocardium and profound vasculogenesis/angiogenesis in extracellular matrix patches, and scar formation in Dacron. Bland-Altman analysis demonstrated good interobserver reproducibility with minimal bias (strain encoding/peak strain: mean difference = -0.32%, 95% limits of agreement = -1.2 to 0.57, correlation = 0.97; rest perfusion/relative maximum upslope: mean difference = -0.74, 95% limits of agreement = -2.0 to 0.53, correlation = 0.92), along with excellent correlation obtained from linear regression (strain encoding: R2 = 0.93; rest perfusion: R2 = 0.85). CONCLUSIONS With the cardiovascular magnetic resonance protocol, we successfully confirmed early signs of functional myocardial regeneration in implanted extracellular matrix patches. This approach is promising in assessing in situ regional physio-mechanical properties and degree of regeneration of implanted tissue-engineered materials.

Conventional extracorporeal membrane oxygenation therapy in the current era

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Persistent left superior vena cava and cardiac transplantation: Anterior rerouting with anastomosis to the right atrium

Persistent left superior vena cava (PLSVC) is a congenital anomaly resulting from the failed regression of the left anterior cardinal vein and the left horn of the venous sinus. Its prevalence is 0.4% in the general population and as high as 13% in patients with congenital heart disease. It is a benign anatomic anomaly but must be addressed during certain cardiac procedures. It is especially challenging in orthotopic heart transplantation (OHT), as either a surgical redirection or preservation of the PLSVC drainage is required. We present a surgical technique of rerouting the PLSVC to the right atrial appendage with bicaval OHT. A 64-year-old woman with non-ischemic cardiomyopathy with a history of mitral valve replacement underwent OHT. The presence of a PLSVC was diagnosed at the previous operation. The PLSVC drained into the coronary sinus, and there was an absence of the bridging vein connecting the right and left superior vena cava (SVC). After a median resternotomy, cardiopulmonary bypass was established with bicaval venous drainage from the right SVC and the inferior vena cava (IVC) and arterial return to the proximal aortic arch. After the aorta was clamped, the right atrium was opened, and pump suction with a pericardial sump (DLP 20Fr; Medtronic, Minneapolis, MN) was utilized in the coronary sinus for venous drainage of the PLSVC. The aorta, main pulmonary artery, right SVC and IVC were transected. The heart was excised at the left atrium leaving enough of a cuff to encompass the pulmonary veins. The PLSVC and coronary sinus were isolated from the atrioventricular groove as a long tubular conduit. Care was taken not to injure the PLSVC–coronary sinus conduit, and therefore part of the left atrial wall was left attached as part of the conduit (Figure 1A and B). It was neither necessary nor possible to ligate branches of the coronary veins draining into the coronary sinus during this dissection. The PLSVC was fully mobilized at the pericardial reflection to avoid possible kinking. A routine heart implantation was performed with the bicaval anastomosis technique. The

High-resolution multi-breath-held 3D volumetric T1 mapping acquisition: analysis of T1 measurement reproducibility compared to 2D T1 mapping with a respiratory motion phantom

Background Myocardial T1 mapping, which is used to detect diffuse fibrosis and quantify extracellular volumes, often employs 8-10 mm 2D slice acquisitions. However, this may be unsuited for accurate quantification of small tissues samples. We propose a new methodology that improves through-plane resolution using a novel 3D acquisition technique over multiple breath-holds. In this study, we compared this new approach to the reference multi-slice 2D approach using a respiratory motion phantom. Methods The proposed 3D sequence employs a Cartesian projection of radial sectors, where each opposite sector pair is acquired in a single readout crossing through the center of

High-resolution multi-breath-held 3D volumetric T1 mapping acquisition: analysis of volume measurements of small structures using a respiratory motion phantom

Background Myocardial T1 mapping is performed using 8-10mm thick slices; however, this is unsuited for accurate quantification of small structures. We propose a novel 3Dpulse-sequence with improved through-plane spatial resolution. In this study, we use a respiratory motion phantom to compare the accuracy and precision of volume measurements made using this 3D-sequence against a reference 2D-technique. Methods