Walter D. Boyd

Reconstruction of pulmonary artery with porcine small intestinal submucosa in a lamb surgical model: Viability and growth potential

OBJECTIVES This study investigated the time-dependent remodeling and growth potential of porcine small intestine submucosa as a biomaterial for the reconstruction of pulmonary arteries in a lamb model. METHODS Left pulmonary arteries were partially replaced with small intestine submucosal biomaterial in 6 lambs. Two animals each were humanely killed at 1, 3, and 6 months. Computed tomographic angiography, macroscopic examination of the implanted patch, and microscopic analysis of tissue explants were performed. RESULTS All animals survived without complications. Patency and arborization of the pulmonary arteries were detected 6 months after implantation. There was no macroscopic narrowing or aneurysm formation in the patch area. The luminal appearance of the patch was similar to the intimal layer of the adjacent native pulmonary artery. Scanning electron microscopy showed that the luminal surface of the patch was covered by confluent cells. Immunohistochemical examination confirmed endothelialization of the luminal side of the patch in all of the explanted patches. The presence of smooth muscle cells in the medial layer was confirmed at all time points; however, expression of elastin, growth of the muscular layer, and complete degradation of patch material were detectable only after 6 months. The presence of c-Kit-positive cells suggests migration of multipotent cells into the patch, which may play a role in remodeling the small intestine submucosal biomaterial. CONCLUSIONS Our data confirmed that remodeling and growth potential of the small intestine submucosal biomaterial are time dependent. Additional experiments are required to investigate the stability of the patch material over a longer period.

Transcatheter Annuloplasty for Mitral Regurgitation with an Adjustable Semi-Rigid Complete Ring: Initial Experience with the Millipede IRIS Device

ABSTRACT Background: Complete, semi-rigid annuloplasty rings result in more durable reduction of mitral regurgitation (MR) over time than partial or flexible bands. We herein report the initial experience with the IRIS transcatheter adjustable semi-rigid complete annuloplasty ring. Methods: Seven patients were treated with the IRIS ring. Inclusion criteria included: 3–4+ functional MR, symptomatic New York Heart Association (NYHA) II–IV, and left ventricle (LV) end systolic dimension ≤ 65 mm. Exclusion criteria included: left ventricular ejection fraction (LVEF) < 20%, aortic valve disease, right-sided heart failure, and pulmonary artery systolic pressure (PASP) > 70 mmHg. Baseline and 30-day transthoracic echocardiography and computed tomography (CT) imaging was performed. Results: In Phase 1, four patients had surgical IRIS mitral ring implantation, and two had rings placed for associated functional tricuspid regurgitation (TR). In Phase 2, three patients had transfemoral, transseptal delivery of the IRIS mitral ring. There was no procedural death, stroke, or myocardial infarction (MI). One patient from Phase 1 expired 2 days post-procedure from chronic renal failure complications. The mitral septal-lateral (SL) diameter was reduced from 38.0 ± 4.1 mm to 25.9 ± 4.9 mm at 30 days (31.8% SL reduction, n = 7). MR was reduced from baseline 3–4+ to 0–1+ in all patients at 30 days. There were improvements in NYHA class, and there was a decrease in diastolic LV volumes from 182.4 ± 54.3mL to 115.3 ± 98.8 mL at 30 days (36.8% reduction). In the two patients with tricuspid annuloplasty, TR grade and tricuspid annular diameter reductions were baseline 4+ to 1+ at 30 days (37% annular reduction) and baseline 3+ to 0 at 30 days (36% annular reduction). Conclusion: This initial experience with the Millipede IRIS adjustable semi-rigid complete ring has demonstrated robust reductions in the mitral SL diameter, MR grade, and LV volumes.

Interstitial lung abnormality is prevalent and associated with worse outcome in patients undergoing transcatheter aortic valve replacement

BACKGROUND Interstitial lung abnormality (ILA) is found in 5-10% of the general population and is associated with increased mortality risk. Risk factors for ILA, including advanced age and smoking history also increase the risk for aortic stenosis (AS). Transcatheter aortic valve replacement (TAVR) has become an increasingly utilized intervention for patients with severe AS, and requires a high-resolution computed tomography (HRCT) of the chest to assess aortic valve dimensions. OBJECTIVES To determine the prevalence and clinical significance of ILA on HRCT performed in patients referred for TAVR. METHODS Consecutive pre-TAVR HRCTs performed over a 5-year period were reviewed. ILA was defined as bilateral, nondependent reticular opacities. All-cause mortality among TAVR recipients was compared between ILA cases and non-ILA controls matched 2:1 by age and gender using Cox proportional hazards regression and the Kaplan Meier estimator. RESULTS Of 623 HRCTs screened, ILA was detected in 92 (14.7%), including 62 patients that underwent TAVR. Among ILA cases, 17 (27.4%) had a typical or probable usual interstitial pneumonia pattern, suggesting a diagnosis of idiopathic pulmonary fibrosis. Survival was worse in ILA cases compared to non-ILA controls (p = 0.008) and ILA was an independent predictor of mortality after multivariable adjustment (HR 3.29, 95% CI 1.34-8.08; p = 0.009). CONCLUSIONS ILA is a common finding among patients with severe AS and is associated with increased mortality in those undergoing TAVR. Further research is needed to elucidate the biology underpinning this observation and determine whether ILA evaluation and risk stratification modulates this mortality risk.

Combined MitraClip Edge-to-Edge Repair With Millipede IRIS Mitral Annuloplasty

Because multiple mechanistic etiologies of mitral regurgitation (MR) frequently coexist, there has been interest in combining or sequentially staging transcatheter approaches to eliminate MR. Combined therapies can be performed together at the time of initial treatment, or they can be staged for the

Clipping the Ring: Transcatheter Edge-to-Ring Mitral Valve Repair in a Patient With Prior Mitral Annuloplasty Ring

A 68-year-old man and observant Jehovah’s Witness was referred for transcatheter mitral valve repair for recurrent severe (4+) symptomatic (New York Heart Association functional class III) mitral regurgitation (MR) after previous surgical mitral valve repair. Two years before, he underwent

Initial clinical experience with the FlexPoint Steerable Transseptal Needle in left-sided structural heart procedures

The purpose of this study is to describe the initial clinical experience with a steerable transseptal needle (STSN) for left‐sided structural heart procedures.